Take a deep breath.
Trust me, the fear and worries are way worse than the reality.
Don't be too concerned about looking like an amature. A super sprint tri will attract people who want to try-a-tri... the pros probably won't be there... so most of the people are in the same boat as you are.
1) transitions (what if I can't find my stuff or can't get my wetsuit off or start my run with my helmet still on???)
Practice transitions at your house. And actively tell yourself that you will take your helmet off when needed. If you are worried you won't be able to find your spot... buy a helium ballon the day before (get one of those silver ones it will last) and tie it to your area on race day.
2) what if I fall off my bike (just recently had my first fight with some railroad tracks and would hate to fall in front of a crowed during a competition)
You will not fall off your bike. See yourself being strong on the bike and not falling. AND... if you do fall... then so what... you get back up and keep going. You won't be the first or last to fall off your bike in competition.
3) Getting beat up during the swim (I looked at alot of threads about this and I think I've already decided I'm going to swim to the outside)
Stay to the outside, swim a little extra.. you will be fine. Plus, you won't have too many highly compeitive people there... so they will be less aggressive.
4) getting lost (is the bike and run usually pretty well marked?)
Well, the path will be well marked. Volunteers will point the way.... and.. unless you are in first place... you will have people to follow. Trust me, you will NOT get lost.
Relax... have fun... remember to smile when you race and thank the volunteers. Talk to your fellow competitors... and you will find that you aren't alone in your fears.
Good luck!
"Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather, to skid in broadside thoroughly used-up, totally worn out, and loudly proclaiming: WOW WHAT A RIDE!!!!"