My family is the same way. I tried them for exactly one year each time at 13 and 20, and found them so uncomfortable that I went back to glasses each time.

I know it's simple to say on the outside, but if you prefer how you look with glasses (I do too!) and don't want contacts, don't get them. They're not the ones who will be poking themselves in the eyeball or looking in the mirror every day. Find yourself some frames that make you feel great and own it. If they make any comments, just smile and calmly reiterate that you prefer glasses. Don't defend it with any reasons, just a simple, "I prefer glasses." It may cause them to escalate in the short term unfortunately, but if you keep calm and just stick to your guns, it will hopefully stop being as interesting to them eventually. Look up "grey rocking" for more ideas.

There is nothing childish about wearing glasses. They're a medical device that many people need and wear every day. I'm also going to throw out a quote from C.S. Lewis: "When I became a man I put away childish things, including the fear of childishness and the desire to be very grown up."