I promise - nerves are way worse than the actual thing. The only time I remember anything being bad was when I woke up from surgery and the nurses were there waiting to give me water and push pain meds. I went out to dinner with my mom...
I am 21 and just had my reduction two weeks ago. Good luck! I am almost 8 inches taller than you and I was wearing the same size - I am so much happier now and I can only imagine how much better you will feel!