There seems to be some toxicity in this thread, primarily over the use of 'closet', but looking past that I relate very much. I think my parents know I'm straight (they'd probably disown me if I wasn't, honestly, but I am so that's not really the issue.) Maybe this comes down to having never had school 'girlfriends' or shown any interest in relationships at a young age, while my younger brother seemed to have a new one every week. This, combined with not really developing 'crushes' until probably a little later than normal and never being in a relationship a little later into teenagehood, has created (a knowingly very stupid) block for me to ever talk about relationships with them. It may also be rooted in younger siblings' 'relationships' and me thinking my parents are likely to compare theirs to what I may have, as in not taking it seriously.
Anyway, while your wording may not have been the most delicate, I do know where you're coming from. A lot of people are saying to 'grow up', but I know too well that some parents are just not really open to having discussions about that sort of thing with their kids.