Cousin and I cuddle/share beds a lot— platonic or more? Mixed signals confusing me

She seems to like sharing a room or sleeping over in general. For example, there was this one time when I was chilling in her room, and she asked if I was going to sleep in there with her. I said no, so she tried to brush it off by jokingly saying, "Ugh, I didn't want you to sleep in here anyway."

Sometimes I get her to cuddle with me while sleeping, but I think she sees me more as a little brother or even an infant-that's just how she is. I don't see it in any weird way, but I did smack her ass once and played it off as a joke.

She got a bit upset, but she was still speaking while softly chuckling and smiling, telling me to get out (still laughing). I stood my ground, insisting it was a joke, but she ended up calling my friend (she's giving mixed signals).

She asked if it was normal for stuff like that to happen (still with a laughing and joking tone), and he thankfully said yeah (thinking she was kidding-holy wingman on his part). So she just let it go, and I still stayed in her room afterward. The confusing part is we've both been sexually active with exes before. She knows from experience where cuddling, sharing beds, and constant touching can go-yet she's still super comfortable with it. And since she knows I've had sex too, why would she keep treating/viewing me like a little brother or baby? It doesn’t make sense. But I’ve been thinking about these mixed signals a lot. Is it something that could be more? Or is it just a regular cousin dynamic?

We also just recently came back from a vacation, and she seemed very attached to me. She wanted to sleep in the same bed, we spent every car ride next to each other, and physical contact has become pretty normalized between us. She hardly reacts when I touch her anymore (but in a good way, I think-this could be positive). We share a close cousin bond plus some extra things that intimate couples would do, but the mixed signals still throw me off and leave me confused about whether I should advance or stop in my tracks.

That's why I came to Reddit to ask for tips on how to build that kind of relationship or do things with her that are intimate but not enough to get in trouble.