Trying to convince my mom to let me get contacts...?!

Ok, so I got my glasses back in late October and vision had really gotten bad at that point. As of right now I'm very nearsighted, like almost blind even 4 feet in front of me but I can still read this right in front of me. So we knew I would need glasses and I said I would really prefer contacts and it wouldn't hurt to try since it just costs a little more than a pair of glasses. My mom and dad both wear glasses but are "afraid" of contacts and just simply won't even touch their eye! So my mom said i should get used to correcting my vision before I tried contacts, so they made me get glasses. But now it's been a few months, and I asked my parents if for my birthday which is coming up I could get contacts and that would be it. Here's my reasons:

~ I'm not afraid of contacts and glasses definitely get in my way
~ I swim, and I don't have optical goggles (they don't work as well)
~ During P.E./Swim Dryland Training, I need to take off my glasses so they aren't scratched or sweaty, but then I can't see.
~You just don't understand how much I depend on something to see mom, where you always take off your glasses and can still read a highway sign.
~ It means a lot to me, since I'm begging for this over a cell phone.

Does anyone have some other tips to convince my parents? Are they being reasonable? Btw, I'm turning 13, and I'm very responsible, in gifted classes, and currently have a 3.8 GPA.