Hi,
I have been on both sides of the fence. I was once a student midwife and needed a woman to follow through and I have been a follow through client.
It is so important to have women, like yourself, to be able to learn continuity of care and holistic care. I had a really wonderful woman. It was her third baby and my first 'catch'. I learnt so much from her. She had a very successful normal, natural birth.
Women are not asked lightly to be follow through clients. If a midwife asks you, she must have seen some qualities in you that she thought would be good for the student.

When I was pregnant with my forth baby, I was asked by the educator (and my midwife and friend) to be a follow through client. I said yes straight away. The student midwife was wonderful. I didn't see her very often but when we did, David and I got along with her very well. We went to her wedding and a week later, she was there with me as I birthed William. She was very much a part of his birth and I will be grateful to her forever.
When everything went wrong, she didn't shy away, she was right there with me. I was really lucky. She kept in contact and we became good friends for a while there. She was one of the very special paople who got me through the first twelve months after he died.

I really think you can't go wrong with a student midwife following you through. You get the best antenatal care because she will want to know all about you, she will want to give you good continuity of care.
You will be good for her too, you can give her some very special memories and good experience. You will help to make her a great midwife.
Good Luck!