Hi,
I was bf till 5 months and I think it is difficult to know if they are getting enough food, so I too was bf 2-4 times a night. My ds is on formula now, so I know how much he has eaten. I started to df at 6 months as I was still getting up in the night, after a sleepless night of pu/pd, the next night he slept through. He too wakes at 5-5.30 some mornings, I leave him to stir and he generally puts himself back to sleep. If he starts to howl I go in and many times he needs his nappy changing, but if not I give him water and he will go back off to sleep. You may want to try not feeding lo, if you feel confident she has eaten enough. M ds was 6 months before taking solids, I gave him jars for a few days on the advice of a friend, which he ate verociously! Now he eats all my food.