What prevents stretch marks ... I'm 4 months should i start applying cream or oil now ?

Yes even if you don't see anything it will prevent it

You can use creams and such but it's also up to gentics I've used everything and still got stretch marks

After every shower lotion your belly twice with Vaseline lotion I've been doing it and I don't have any

I'm using 100% african Shea butter

I did everything and still got them but my mom got them bad too...it's in ur genes