Weight gain, stretch marks and working out!

Hi y’all!!! So this pregnancy I have been gaining a ton of weight in my legs and my arms and not much in my stomach! I am getting stretch marks all over my legs and hips. I have been using lotion and cream. I know this is part of pregnancy but I was wondering if there is anyway to prevent it or help it! I also would like to work out my legs and arms but I do not work out at all so im wondering if y’all have any tips or tricks for me! I am 25 weeks pregnant with my first!