Friendship with Former Teacher?????!!!!

I finished school a month ago. My teacher and I always had a good professional relationship. She helped me a lot with problems and my confidence. Last year I used to teach her classes along side her and run errands for her. She calls me her personal Assisant. I went away a few months ago while I was away I emailed her on her school email to make sure I was all caught up with work etc from that she had my personal email address. I had problems a few months ago also and she went to the school councillor with me and explained everything. She emails me to tell her classes she will be absent and she calls me a star and amazing. I've know her for 4 years now. While I was still a student at school and her student I added her on Facebook as a joke. Then I was going to leave sixth form so I added her in the summer but I went back to school to finish off my a levels so I deleted the request. I officially left school and she stopped teaching me a month ago. I added her about 4 days after she stopped teaching me. She didn't accept so again I deleted the request. I've seen her since then because I popped back to give her a goodbye card and present. She thanked me and gave me a big hug. She sent a picture of her thank you what I had wrote inside to her boyfriend. I told her I probably wouldn't see her again and she said I would. I asked her if we could stay in touch and she said yes but that she's always so busy with her now being Assisant headteacher. I saw her again a few days ago I went back to school to wait for my friend and asked her what her boyfriend said about the card and she told me that he thought it was kind of me. I told her to enjoy her summer and she said "You too Hun." I won't see her again now for a long time. I don't want to add her on Facebook because she will think I'm weird. She has two mutual friends with me on Facebook. A girl from my class this year but she was from a different school she came to my school for lessons and another girl who was in my class two years ago. Both former students of hers. I went to this teacher for everything. She really has inspired me and taught me to be confidant. When I saw her I also wished her a happy birthday for Tuesday (23rd June) last year for her 30th Birthday I bought her a card and some chocolates because it was a big birthday and she had given me a chance to shine in our school play by giving me a main part. Also this year, she bought me a bouquet of flowers for my 18th Birthday. She's always been so supportive and kind towards me. And I really do look up to her. I don't fancy her or anything she makes me smile and makes me feel good about myself. I don't mind staying in contact with her through school email but I would like her as a friend on Facebook so we can least have some sort of friendship. I'm scared of adding her again though because it would be about my 4th time trying to add her. Can I have some advice? Does it sound like she wants to be friends? Sorry it's so long!!