The standard protocol is to wait 12 months if you're under 35 and 6 months if you're 35+. There are exceptions to that though (eg you can go earlier if you have a pre-diagnosed issue or evidence of back-to-back annovulatory cycles).

At your age, I'd be asking my GP for a referral ASAP. I only waited 6 months last year (36yo and diagnosed with endo). I waited 12 months when we were TTC#1 (31yo and no known issues, although I did suspect endo but several GPs had dismissed the idea).