Hi, and welcome to the forum!!

I'm sure you'll get lots of opinions around here, but basically different things work best for different people--and you get equally as wet in all shapes One thing you might want to consider is whether or not you plan to use a cover, or a solar blanket for the pool. They're going to be much easier to get and much less expensive in a standard shape pool than in a custom shape.

Our pool is a simple rectangle, hopper-shaped pool that goes from 3 1/2 ft to 8 1/2 ft. We put it in when our kids were 2 and 4. If I had to do it over again, I would build the exact same thing.