Whatever you choose, I think it's good to note that sexuality is a spectrum. Social biases codified our attraction, even though it's contrary to the biological facts.
I think, personally, if you want to come out but you don't know what to say then you should say that you don't like labelling. Bisexuality can fall anywhere on that spectrum, it's not always 50% into both, but having said that you could just be 100% gay.
So yeah, I think you should say that you don't like labels, and if you definitively discover that actually you're 100% gay or somewhere on the bisexuality spectrum you have the opportunity to come out again as that, instead of maybe coming out as the wrong thing in the first place and then have to correct yourself.
I really hope I helped, sorry it's a little long winded, I hope it makes sense.
Best of luck x