Definitely make sure that YOU are happy with the suit fit - don't just rely on the "store expert."
I posted a few times recently on how the very experienced older clerk at the Santa Monica triathlon-specific store told me my suit fit "perfectly", even though I told him it seemed very, very tight. I could not zip it up on my own, and my arms were really restricted over my head. Sure enough, in open water, my arms were exhausted within 100 meters - even though I normally swim no problem for 1-2 miles in a pool.
I kept at it 4 more times, thinking it was my bad swim ability, but it never got any better, whereas I got better in the pool. I finally went wetsuitless 10 days ago, and was right with the main pack, for nearly 2 miles, and almost no significant fatigue.
Went to a sleeveless wetsuit, and haven't looked back since. It was definitely the unfortunate-fitting wetsuit - nothing I did in terms of pulling it on, up, around, made it better, but I got a new Xterra sleeveless
($140 on sale - right now if you can find the sale ad; I believe it's on sale until June
) and it's been great. No problems at all.
It should feel snug, tight, but definitely comfortable and nonrestricted even out of the water. If not, try on another suit for sure no matter what anyone tells you.
Last point - I'm surprised with how well one can swim sans wetsuit, given summer temps. I swim in the Pacific ocean off LA, and the warmer temps are definitely wetsuit-free no problem in general as of now.