I personally wouldn't find it creepy. I'd be flattered...at least, at this point in time I would be. But there is nothing wrong with sending a sweet, simple note with well birthday wishes.
...Scrapbooks are not always a good thing, but some actors do keep them! Condensed version of a story I could make long: There is this actress, and I started out as a fan. I recognized her in NYC blocks away from her theatre, and it went from there...we chatted, exchanged emails, and she got us tickets to this show she was in that tickets were impossible to get (house seats, we paid). I made her a small scrapbook PAGE (Not book, mind you) as a huge thank you. She told me she would put it in her dressing room, she seemed thrilled! So I was just like, no problem, thank YOU, thinking she'd throw it somewhere and forget about it. So to sum it up, weeks and weeks later I came across a video where BWW went into the dressing rooms of her show, and believe it or not when they went into the dressing room this actress share/d/s with two other actors, there it was sitting in the corner by her hairdryer! I played the video multiple times and took screen captures...nothing creepy about that, I was pretty ecstatic. The end. I think it has to do on the level you know them, too. I only contact actors if I have a serious question or want to let the ones who remember me know I'm headed to the city.
By the way, I watched that video....very creepy.
"Sing 'till you're breaking glass or you're breaking down"