hiya, I co sleep with DS2 who is 13m. I have a bed rail on one side then me on the other! he can crawl off the end but TBH if he is that wide awake he seems to wake me before he gets very far. I think the temptation to come and pat my face is more than the desire to explore the end of the bed!
if there isnt time to get hold of a bed rail can you put the mattress on the floor? thats what we are doing this week as on hols and I forgot the bed guard. DS2 is on the side where the mattress is against the wall.
alternatively if your bed isnt too high could you just pile up pillows on one side of your dd so she cant easily climb over?