I haven't read all the posts, but I had to respond. If you feel called I say go for it! my first doula was AWESOME and she hadn't had her own yet. my midwives were incredible but it was my doula who got me through the birth of my first child. I will forever remember looking at her when I was pushing.
I hope you go for it. my guess is there are plenty of women who will not consider it necessary for you to be a mom already.
Jenny