Using tampons doesn't make you more grown-up, what will make you feel more your age is having the confidence not to give-in to peer pressure, educate yourself and make your own choices.
Tampons are a major hassle - you need to change every 4-6 hours, they can't be worn overnight, can't be worn with light flow, can't be worn if you have a vaginal infection, can't be worn before your period, you have to make sure to use the right absorbency, you need to alternate with pads...plus tampons leak so many women use pads as back-up too...so you'd be switching from pads to tampons and pads, if you're fine with pads there's no reason to complicate things.
Not everyone follows the precations, but my sister works as a gyno and sees how that effects women's health, whether they know it or not tampons always have negative effects on vaginal health, and not following precautions is even more unhygienic and unhealthy.
Tampons are linked with TSS - this is rare, but not nearly as rare as is made-out - tampons commonly cause vaginal infections, there are potential long-term health risks to the chemicals used in commercial brands, irritation from chemicals used in commercial brands, and tampons can also increase menstrual flow and menstrual cramps too.
Have you considered other options; menstrual cups, softcups, sponges, etc. - tampons don't make you more at peace with your body, they go against your vagina's basic functions which is why they are a risk; dry-out your vagina, encourage massive increase in bacterial growth, prevent vaginal cleaning, and effect vaginal pH.
Menstrual cups are a FAR better option...I seriously suggest if you're going to use something internal you look at these rather than tampons. Menstrual cups are internal like tampons but totally safe so no health risks at all, they can even lessen cramps and flow, they thus can be worn for 12 hours, with any flow, before your period, overnight, and no need to alternate with pads, plus they don't leak like tampons or pads do either. Much better than tampons!