Am I a side piece ?

I started dating a guy and we’ve never gone out, he’s only invited me to his house at 7pm. I met him on tinder and after the second date we decided not to see other people and after the 5th date he asked me to be his gf. We haven’t been anywhere else besides his house and he won’t add me on any social media but he’s admitted to stalking it. He did plan a trip for us, that he’s paying for during the winter. I planned a hike for us the week. I’m not sure if I’m overthinking it.