Hair growth?

So I've always had long-ish hair and I always wanted mine to be super long! But i cut it to my shoulders and for the past year its been the exact same length and it won't grow anymore! I'm scared to trim it because I think it'll stay that way. How do I get my hair to grow longer?!?! It's healthy, I haven't dyed it in a year and a half, it just won't grow! 😢