lol sounds like your daughter needs to speak to someone whose had them for more than 8 years & has the experience to say whether or not it's a good idea.
Whether or not you think your daughter will look good with them should be irrelevent. She clearly thinks she will. She may get the piercing when she is older even if she is a teen. The best thing is to try and wait it out for at least 6 months to 1 year. If she still wants the piercing then allow her to get it. Otherwise, this could be just a fad or trend she is interested in now, but will regret later. Oral piercings are different than an ear piercing (however you can't clear up the holes entirely on those, cartiladge heals well on the ear tho like a helix piericng). There's long term effects to consider.
You & she have to consider a few things. Over time her snake bites (& tongue piercings) will cause tooth decay. The piercing rubs over the teeth constantly eroding the enamel & the gums, it also dries out that area of the mouth causing cavities & other dental issues. It starts with tooth sensitivity, if your daughter already has sensitive teeth I don't recommend it. Additionally, if your daughter does or should she decide to smoke cigarettes it will increase the amount of oral health issues she will have. If she does smoke before she gets the piercings it may effect the way it scars. The scars are usually thicker. That's why you are told before and after every surgery not to smoke. So these are some things to consider. Make sure your daughter is properly educated about these things. Most girls have them in for a few years, they get some dental issues, or they don't clean them properly so they have a few infections that cause the wound to puff up/ooze/discharge/turn reddish pink/or what we call the volcano effect (looks like a crater with reddness around the area).....& after any of these happen for a few years or their dentist informs them it's due to their piercings they usually take them out.
I've done piercings for 10 years. You are supposed to be informed of these risk before you & your daughter make the final decision. In teens, we are supposed to encourage our teenage customers and their parents to take at least 24 hrs to reconsider the piercing. If you do choose to allow her to ge the piercing be sure to go to a reputable shop that follows the rules b/c most don't. & if your daughter does have issues take her to the doctor. They will ask her to remove the piercings. If she goes to a shop they will ask her to leave them in while it heals & it can cause more scarring/infections. Even if you are given the proper solutions to clean the piercing. It is a safe place, but if you do end up with an infection or scarring it's best to take the piercing out immediately and allow it to heal. She may get it repierced near the scarred area. Re piercing scar tissue or infected tissue is not recommended. If her infection, redness, puffiness, and oozing doesn't reduce within a few days of using the solutions please visit your emergency room/urgent care center. Your daughter may be allergic to the metal in the piercing even if it's hypoallergenic.
If the piercing does heal well I would recommend your daughter see a dentist every 6 months even when she's an adult. She should not smoke. She needs to drink plenty of water constantly throughout the day to keep her mouth moist. She needs to clean the piercings constantly (2-3 times a day, when she wakes up, after she eats lunch, and before bed - forever), even after the initial period. She might want to try sensodyne. She needs to avoid acidic foods & drink. This will help her avoid any extra damage to her teeth. Also she won't have to worry about infections later on. & another thing to consider since she is young. Black heads and pimples. Around the piercing. She can't pop them, she needs to use an extractor. Her fingernails will cause a mean infection/redness/swelling/bleeding. She may have some that literally grow right on the piercing and cause pain when the piercing is in. It's pretty nasty & she will have to take the piercing out. If it scars ( the pimple) she might not be able to put the piercing back in. That has happened to a few of my customers whose parents allowed them to get theirs at 14. At about 16 they were back in the shop asking for help & we needed to repierce it, creating a new hole next to the orignal. The original scar was pretty nasty, but everyone scars differently. The issue is it's on your face so it's very noticeable.
Additionally, she may not be able to get certain jobs in the future. I've had friends take them out because they wanted to work in an office or at a nicer place. One friend actually had to change for work once, she was going a bit fast & she ripped one of her piercings out b/c it got caught on a string on her shirt. She was fired b/c she had a medical emergency in the middle of a busy day.
Some places say they will hire anyone, but they can, have, and will really scoff behind the persons back just b/c they have a piercing, or worse a scarred piercing. You both have to consider this. Fortunately, some places do ask you to just take them out, or they will allow you to wear them. But a face piercing is a face piercing. It's nearly the business equivalent of a hand tattoo. It has to be covered up on most occasions, or they just say thanks for the interview and whisper (what was she thinking wearing that in here). At least that's my managerial experience. It's sad, but it's a fact. People discriminate - even businesses.
So now that you know what to consider, please do reconsider with your daughter. Snake bites are really great, like any piercing, but she really has to understand the weight of her decision. Most people don't consider all of this BEFORE getting the piercing, they just run into the issue after. Yes, they look awesome, but if that's the only reason - and you have this list of other reasons...she might not want it in 5-10 yrs if you know what i mean. & that's always the reason for reconsidering a piercing. What will she want somewhere down the road. So please make her sit on it for some time before actually letting her get it. It does bleed a lot so she shouldn't freak out during the procedure. They are really cute, but not everyone is open to them.