conditioning is your strong point. don't overwork yourself too much from here on out. you should fill out quite nicely.
stay in the jr category. don't jump into the open. your shoulder/ waist ratio is sick and you have the genetics to go far in this sport should you choose, but take your time to develop.
you are going to place well, very well. my advise is to take a year off and bring up your legs, top to bottom, front to back. and your tri's. your shoulders and chest are so overpowering they make your arms which are not bad at all seem so at first glance, but you'll need alot heavier tri's to balance out the sick shoulder width and make everything flow.
you just need time to fill out. you have the potential and the frame which is half the battle alone.
best of luck in 2 weeks, not that you'll need it. just stick to what got you this far. don't hit the panic button and coast in and everything will fall into place.