It's worth sticking with. I wasn't feeling it at first with my current girlfriend; I honestly could've taken or left sex. But after a few weeks and a couple of months we found our rhythm (no pun intended) and now it's probably the second best sex I've ever had (and there's no shame in being second to the best sex I've ever had). See how it goes in the coming few weeks and if you're not feeling it then make a decision.