I think if I was choosing a doula, I would do so looking at a number of things like:
- qualifications
- if they came recommended to me
- their experience
- how I connected with them, and how my partner did
- if they supported my wishes and I felt they'd be firm enough to advocate for me.

I think if someone was warm, professional, and knew what they were doing, I could have confidence in them no matter what their age. My birth support partner was 18 when I had my first baby (she was a student midwife then) and she was an excellent support, I couldn't have asked for better. So it is possible, but I think you would need to decide whether you could convince women that you have that special something that makes you worthy of sharing in their birthing experience.

All the best.