So, I'm questioning. Now what?

It seems like every piece of advice that is given to questioning folks is to just "go out and try it!" And while I appreciate the support greatly, I feel like a domesticated hamster being set down in a forest and told to run free. I want to try being with a woman sexually, but I've never been physically intimate with someone that I wasn't dating. (I've also only dated one guy who made me feel really shitty about my body.) I certainly like the idea of dating girls, but how could I live with myself if things got hot and heavy and all of a sudden it's clear that this isn't for me? I mean, I know if the tables were turned, I'd be really hurt. Is casual sex a good idea for someone who is questioning? Does anyone else have experiences that they can share with going from being questioning to being certain? The idea of casual sex sort of puts a knot in my stomach, but it seems to be very popular across all genders and sexualities.