Is this the right suit for me?

I am marrying and I am in need for a proper attire.

The Shop assistant suggested me this 3-piece outfit consisting of Pants, Vest and Suit.

He suggested tailoring for the neck and shortening the arms/pants.

It feels comfortable all around but I feel like it looks rather tight in the middle area.

Would losing some pounds before the wedding be enough to make it look less packed?