Re: How to help my 13 yr old fall asleep?
Can you have the 11 year old go to bed a little earlier than the 13 year old, so that she is already asleep when the 13 year old goes to bed?
I have an almost 3 year old, 4 1/2 year old, and almost 8 year old who share a room (their choice, they could each have their own rooms), and sometimes we have this problem too - although it sounds as if the issue with your 13 year old may benefit from some medical advice. Have you asked a doctor about it?
We play music in our girls' room at night, and make sure that they have enough night lights. I also find that if their day includes physical activity, and a limited amount of sugar, they go to sleep more easily. If they are too noisy for too long, I start to threaten that I will take the most offending person out of the room to sleep by herself for the evening (I make sure to follow through immediately). I don't have to follow through very often, because they know I mean business.
Another thought is to perhaps try some sort of relaxation routine. Maybe do a few yoga moves with her at night? Give her a little relaxation massage? Have her read a little before bed?
Those are my thoughts. Hope something here is helpful for you.