Nah, you're not too old.
Although I don't sleep with mine, I still have many of my stuffed animals from when I was little, and I am still very much attached to them.
I have a clown that went through an X-ray with me when I was 5.....lol
In addition to animals, I also have a small blanket that I used when I was little, that I still have. It's a tiny little thing, I was probably still in my crib when I used it.
I have another blanket that my Mom got me when I was 5 years old. On the way home from school (Kindergarten) my mom told me she had a surprise for me, and I'd find out what it was when I went to bed that night. I kept asking her what it was and she wouldn't tell me, just said it was something on my bed....lol. She had gotten me a new blanket and wanted it to be a surprise. I still have the blanket, in fact I used it up until a couple years ago. It's worn down so thin that you can practically tear it with your hands, but I'm too attached to it to throw it away, so i have it folded up and just stored in the closet with the rest of the blankets.
It's funny how we get attached to stuff like that, I just find them a comforting thing. I guess it's just cause they've been with my all my life through good times and bad...lol