If you dont know about NTRP, rate low. Do not read the "NTRP guidelines" unless you just want to punish yourself for a few years. Bottom line is:
-Rating low means you can move up easily, willingly.
-Rating high means you will have to kick, scream, moan, lose, appeal, beg, steal and borrow to come down.
If you self-rate at 3.5, but immediately appeal down to a 3.0 you will probably be ok. If you play one season of 3.5 and one season of 7.0 you will make it dramatically harder to come down even if you managed to lose every single one. If you're a "S" rate and you go... 0W-10L but lost all of those "very close" I dont think they will grant your appeal down to 3.0, but I suppose its possible, but why risk it?
Answer the questions truthfully. You do not want to screw yourself and your team by getting DQ'ed because you lied about something.
When they ask you about "playing high school tennis" they mean playing on a team. Do not answer "yes" to this if you were just goofing off in high school unless you're extremely confident in being able to play 3.5 because that's your minimum rating IIRC.
From your description of yourself I would say try "3.0" if there is a league in your area. Double faulting is almost not acceptable at any level, nor is missing easy put aways more often than not. All of these things are relative to level of course, but if you're doubling on second serve "punches" as you call them, or whiffing floaters at the net, you will have a lot of trouble in 3.5.
If pushers still frustrate you, you will have problems in low levels of tennis. Learning to beat them is almost like a right of passage, regardless of how you achieve it. Facing a pusher is great for temperament and great for consistency. People look down on pushers. That's exactly why they lose. If you respect a pushers game, and dont let your temperament and inconsistencies get you, you can beat them every time.
"In the 1980's two men dominated--sometimes each other, most of the time everyone else."