I have a cousin who is like a sister to me. We grew up together and both still live at home with our family. (We're grown adults)

For this entire month she's been going out with a mystery guy. She hasn't told me about him and seems to be secretive about it. But at the same time, she is an adult and entitled to her privacy. But its soooo obvious she's going out with someone.

The thing that bothers me about it is that she'll randomly leave the house between the hours of 12a.m.-1:00a.m and come back an hour to two hours later.

Last week when she did this. I decided to look out of the window to get a peak at the guy but she got in a car and it pulled off.

Yesterday, I was tired and went to bed late it was around almost 2:00 a.m. when I was headed to bed, I heard a car outside. I turned my lights off and was adjusting my pillows. I still heard a car outside so I looked outside the window (I was looking through a small gap in the window blinds and didn't lift or pry a curtain to make it obvious) and that same car from before was outside. I kept staring at it , squinting to see the fella but couldn't because the car was too far and it was dark outside. Then all of a sudden the guy looks up at my window and begins to stare. I'm wondering if he can somehow see me, well my shadow. So, I stay there looking and he taps the passenger (my cousin) and points to the window and she starts trying to look at the window. I then pull my body back. About 2 minutes later she exits the car and the guy rolls down the window and says something to her but I can't make out what it is. But my cousin's response was something along the lines of "that's my cousin" then he asks what my name was and she says my name and he said something like "tell parking-act I saw her or we saw her (cant figure if he said I or we) and tell parking act I said hi" my cousin laughed and then came inside and went straight to her room.

First of all these late night drives or whatever is a no go! I know! She's making herself so available its crazy and something about last night made me feel uncomfortable.

What do you all think?