Thinking of joining Masters swim team in NYC, have questions!

Hello! I just recently moved to NYC. I've been wanting for a long time to get back into the pool. I swam 5 years in high school. My best stroke was butterfly, decent freestyle sprinter, and not as good of a distance swimmer. I graduated way back in 93, since then I've swam periodically but without a coach/teammates pushing me I find I have trouble staying focused. I've been recovering from a back injury sustained in martial arts training so I've pretty much been out of the pool the last year. I've not in very good conditioning right now so I'm going to have to ramp up. I'm worried about not being able to keep up and/or make it though a practice at first. Would you suggest I swim on my own for a while to build up to a minimum level of conditioning? Or should I just show up at the pool and join a team? After doing some research looks like two potential places to swim with here in Manhattan: AGUA at Asphalt Green and Red Tide. Anyone know anything about these two teams and/or have any suggestions for any others? Thank you so much!