Which swim wave to choose....

Assuming there will be 6 waves, I'd start in the 5th with that time.

And unlike the post above, I'd rather be passed than do the passing.

Not the first one.  Two reasons. 

1.  Let the fast people (and the people who think they are fast  go on ahead).  It's more likely to be a more intense start, and since this is your first, I wouldn't go getting messed up in that just yet.  Any wave behind is going to be full of more people who feel the same way you do. 

2.  Seeing a wave go off might help you calm down a bit before it's time for you to go.

Don't be scared  It's just water.

Just pick one, it really won't matter much.

Why?  Because in situations like this, the likelyhood that a bunch of the field will mis-seed themselves is very high.  It will not matter which one you pick, there will be people that are significantly faster (or slower) then the others in that group.

 Based on your time I'd go with steveseer on this one

Thanks for all the advice everyone...forgot to mention that this is a female triathlon.

 Does the fact that it is all female change the 5th wave recommendation?

 It is pretty absurd. I think the fact that it is an all woman tri you could start in heat 4. The 6th heat will be the "non-swimmers". If you decide to go with one of the earlier waves. Line up on the outside. If you primarily breathe to your right you want everybody else to your right to keep an eye on them. Just the opposite if you breathe primarily to your left.