No you'll be fine, if you are new master the art of falling so you know how to fall well, this will reduce the chance of you having a nasty fall.
Also wear a helmet if you are that nervous, but don't think about it too much, have fun and take your time (especially if it's your first time...btw the first day will really hurt, but it will be worth it)
Plus I learnt when I was 15, after the first day things will get much more easier.