I have totally been there!! Our 2 girls share a room, 6 1/2 and 3 1/2, (who still takes 1 after lunch nap, right after lunch it's quiet time for our 5yr old, and NAP time for her) If she misses her nap, then she goes to bed a little earlier. Our bedtime is 8pm for all three, and the older gets up around 7am, our youngest gets up a 1/2 hr or so later. We were very consistent with our oldest when she was younger and it paid off! But I have to admit with our 3rd, the 3 1/2 yr old, I have laxed a bit. We actually have another between those two, a boy who has his own room. But up until almost a year ago we had all 3 in one room from the time our youngest was 4mos. Anyhow, we have been being more consistent about our bedtime rules, and that makes a huge difference. If they are "allowed" to get up, talk, be rowdy, then that's what they will do. I agree with the other suggestions about putting the younger down a bit before big sis. Say an hour. Although she doesn't "like" sleeping by herself, we all HAVE to do things in life we don't like. That's something we can't get away from. After a few nights of mom/dad being consistent, not allowing distractions, she will learn this is the new routine and will settle into it. We have done this before, and after the 1st night of our youngest going to bed first, we noticed a huge difference the next time they went to bed at the same time. We have allowed our youngest to crawl into our bed a few times. But if it's something you want to stop, it's going to take consistency. That means, every time she comes into your bed, take her back to hers, it may mean many, many trips the first few nights, but she will get the idea, and you will get a peaceful nights sleep! I make exceptions at times for mine to get into my bed, ie. sick, bad dreams, etc. but most of the time, I take them back to their bed, tuck 'em back in, pray with them, (for bad dreams) and go back to my bed. (Mostly because my DH doesn't like them in bed, they wiggle to much :) I figure he has to get up and put in 8+ hours of physical labor the next day, so he need a good nights rest. Anyhow, just my thoughts, and experiences. Hope you are able to find what works for you!