routine

someone please give me advice. If i let my baby go to sleep when she wants downstairs its about half 12/1am but will sleep for hours but i felt its too late for her to go down especially if we have something on the next day so the past few nights i have been trying more of a routine with her, i get her down at about 10 but then shes back up half 10 n every 2 hours after thar and takes so long to go back to sleep as everytume i put her down she wakea up 😭 i try just putting her down n leaving her but she wriggles about and moans that much that she ends up sick everywhere so then im starting again! Also when she stays at my mumd she sleeps 7 hours at a time?? anyone any idea why she does this? Lack of sleep is sooo hard