I was worried about the same thing and then last week DD started putting herself to sleep completely on her own. She'll be 13 weeks old tomorrow.
So maybe it's right around the corner!

DD always liked playing on her playmat (as long as one of us was with her) and then last week she just rolled onto her side and went to sleep. A few days later she was swinging and talking to me while I sewed and I looked up to see why she'd stopped babbling and she'd just gone to sleep. She's done it every day since. It happened that way for a friend of mine too. Baby needed a ton of help getting to sleep every time until suddenly she didn't.
You're definitely not ruining her. You're giving her exactly what she needs and that's setting her up to be completely successful on her own. And that includes going to sleep. She'll get it, and you'll know in the next few months if she's CAPABLE but doesn't know how. Then pull out the books.
Enjoy the extra cuddles for a few more weeks/months!
