Best events for an adult newbie?

What are you swimming work out.  what are you comfortable swimming, and what do you enjoy swimming. If you swim long distance freestyle in work out then enter distance freestyle events. If you concerned you can’t finish a race then enter. 50s or if they have 25s enter 25s. if you like backstroke enter backstroke. If you like breaststroke enter breaststroke, if you like to swim butterfly, swim butterfly. The longer distances of the strokes, 200 breast 200 back 200 fly, I probably going to have the fewest entries. If you’re good at or enjoy any of those, I’d suggest entering those. 

What are you swimming work out.  what are you comfortable swimming, and what do you enjoy swimming. If you swim long distance freestyle in work out then enter distance freestyle events. If you concerned you can’t finish a race then enter. 50s or if they have 25s enter 25s. if you like backstroke enter backstroke. If you like breaststroke enter breaststroke, if you like to swim butterfly, swim butterfly. The longer distances of the strokes, 200 breast 200 back 200 fly, I probably going to have the fewest entries. If you’re good at or enjoy any of those, I’d suggest entering those. 

I endorse what Allan said here, to which I add that you might want to:

1) "Test" the events you are contemplating by giving them a really hard effort in practice. You likely will want to do this to get a seed time anyway, but it will also give you a feel for what you are getting yourself into, how to pace the event, how your body holds up, etc.

2) Check the schedule of events for the meet. It's good to space out your events, especially at a small local meet, to avoid dragging yourself out of the pool all out of breath and having to get back on the starting blocks shortly thereafter.

Mostly though, pick a few events and have fun!

All good tips!! Thanks so much!