Hey there, I come from past experience in trying to do this. Way back in late 2012/2013 when ODing seemed like a normal thing (to me at least) there were plenty of people who tried.
Hell, it’s caused me to instantly dismiss people who look like an old ODer. That is the classic ice leg as well as 2.0 package with a shirt brand and khakis/jeans.
Anyways, like the others said it’s against the rules and you’d probably not get banned but instead teased by friends for saying you have a Roblox girlfriend.
Plus nowadays nearly everyone who plays Roblox is a child so you’d get in trouble really just trying.
Take a step outside, put some good clothes on, try your charm, and then you might get a girlfriend. Good luck man!