It is ageist to say you wouldn't let someone of a certain age perform a medical procedure that you would let someone of a different age do. How isn't that ageist? Why the age 23 anyway? They may be 35 and just retrained as a midwife and only ever performed a few, whereas someone at 22 may have qualified fresh after a nursing degree and being doing it a lot longer.
I do not agree the longer you have been doing something the better you are at it. Caring about what you do and how you go about it makes a lot bigger difference!
If you need one in the first place, is presumably the birth isn't going as smoothly as it should ie. forceps/big baby/heart rate dropping and in need of a quick birth. This means that there would be a consultant or senior midwife delivering anyway!
They would never let a random junior doctor lose on you. If it were to be done by a student, it would be under the close supervision of another doctor. I fail to believe that the pp actually heard the doctor say "she fancied having a go" and if she did, she's an idiot for letting her do it.
At every point a student was involved, I was asked for my consent. When I went in for a sweep as I was over due, the very nice midwifery student asked if she could do it, although there was a risk that she couldn't and the midwife would have to. Same with having my waters broken, I was asked to give my consent first, they would never just let someone who had no training cut and stitch you.
I promise you the best midwives I had throughout pregnancy and labour were the younger ones. They are a lot more enthusiastic, and seemed a lot more compassionate. I suppose it numbs you seeing people in labour everyday, year after year. They also had a lot fresher ideas, like showing me different breastfeeding positions, whereas the original midwife just showed me the traditional one.
Like I said, a consultant messed my stitching up, even though it was done with my legs in stirrups in theatre, which is supposed to be the best place as they have the lighting/time/access to make a good job of it. So the skill of the doctor has nothing to do with age.