“Trying out sex” is not how you confirm or deny your asexuality. It might help you decide whether or not you enjoy sex. It might even help you decide which gender you prefer to have sex with.
But it will not, under any circumstances, confirm someone’s asexuality.
Because asexuality is not about whether or not you like sex. It’s about whether or not you experience sexual attraction.
Stop telling asexual people to “give it a try.”
Stop questioning asexuals based on their sexual history or lack thereof.