| [F straight] think I have a crush on my friend [F - lesbian]. What do I do?

I’m straight and have a close female friend who is lesbian. She’s very supportive and attentive — we spend time together one-on-one (sometimes late at night), she checks in on me often, and she’s been there for me when I’ve needed her (she stayed with me to study when she was exhausted, drove me home from the hospital and recently she put her hand out on the table so I wouldn’t bang my head when I bent down. I mean who even thinks of that?!). She compliments my appearance and has asked more than once whether I’m seeing anyone.

There have been a couple of brief moments of light physical contact (hand on knee/thigh). What surprised me is that I noticed I enjoyed it and started having reactions I don’t usually associate with friendship - like checking my phone to see if she’s messaged or feeling jealous when shes mentioned being asked out by someone else. I’m unsure why I’m reacting this way and whether it reflects anything meaningful or is simply a response to closeness and attention. For context, I told her early on that I’m straight. Which I thought I was.

She’s genuinely a friend, and I don’t want to misinterpret things or make her uncomfortable. My priority is handling this with respect.

My question is: How do I give her a subtle “green light” that I might be open to more, without making assumptions or risking the friendship? Is there a respectful way to clarify whether she sees me as more than a friend versus just being affectionate?

If a guy was doing everything that she’s doing, I would think he was romantically interested, but I don’t know if she is. Or if she’s just being a good friend.

TL;DR: I’m straight and confused about my own reactions in a close friendship with a gay woman. Looking for advice on how to signal openness or clarify intentions respectfully, without harming the friendship.