Does the metabolism start to slow down at a certain age?

I (5’0”) am 24, almost 25. I have maintained the same weight from 17 to 23 with a little bit of fluctuation (92 to 95 pounds).

Just within the past year I have gained over 10 pounds. Once I reached 102 I decided to start working towards improvement. My eating habits weren’t great before, but they didn’t change until two months ago. I cut out alcohol, started my deficit, and began strength training 4x a week while doing cardio on off days. I am growing muscle, but not losing any weight. I am now at 106 and I feel frustrated.

Is weight gain going to continue to be harder to fight off with age or could something possibly be wrong hormonally?