My DS is 8 weeks and we have co-slept since day 1 in hospital when nothing would settle him and midwife suggested taking him into bed. It certainly worked and he has been there ever since. We only have double bed but we all 3 squeeze in somehow.
My boy is a very poor sleeper except with us at night so i haven't thought to hard about long term getting him out - doing what i have to atm to stay sane!
Must admit, i do enjoy him being with me- i know he is safe and i don't get up at all through night - just pop the BB in to feed and back to sleep! DH would probably prefer him out but not pushing at this stage. Just makes private time difficult.
Go with it if you all enjoy it- i am sure she will be on her own happily before 10yrs