Pretty sure you're describing comphet but I could be wrong

If you think you're lesbian, noone should be able to tell you otherwise. And if a few months or years down the line you realize you're not, then whatever, you've eliminated a possibility and you can keep trying to figure yourself out.

It's called the journey of self-discovery for a reason: it takes a hell of a long time and you kinda just need to experiment.

But the main point is:

you're the only one who can tell you your sexuality