At that age, she needs your boobs. She wouldn't do it if she didn't need it, even for a short nursing session.
If the bra is an inconvenience, then either don't wear one at night or get one that just moves over to one side (I wore one of those soft cotton ones at night for a long time with DS)
If the bra is an inconvenience, then either don't wear one at night or get one that just moves over to one side (I wore one of those soft cotton ones at night for a long time with DS)