How and when to go past kissing?

So I’m 19 (I’ll be twenty in a few months) and I’ve been dating my first real girlfriend for about four months now. Neither of us really have any experience so its been sweet but also awkward exploring this whole new world together. We were each other’s first kiss and we make out pretty regularly now but I dont know how or when to initiate a conversation about going further (especially when, if I’m being honest I’m not completely confident we’re doing that right 😂). There’s also the added layer that I was raised catholic and while I’m sex positive now but sometimes the catholic guilt still kicks in a little.