Baby’s sleep

So my daughter is almost 6 months on the 25th. She has a bedtime and does well with that but still wakes up in the middle of the night, not to eat but just wakes up and gets fussy or she’s wide awake. I try letting her get herself back to sleep but eventually I end up getting her and putting her in the bed with me because if I do that she sleeps through the night. At her drs appt today she said not to pick her up at all because she has to learn to get herself back to sleep, my question is if I start to do that how long will it take for her to learn to do it on her own?