My Older Girlfriend

I am 20 old woman and I am dating a 38 woman she so cute and sexy have this huge ass I want to just put my face in it and never let go .
The problem that I have this fantasy to be smother by her ass I want her to sit on my face and let me worship her ass and pussy I want to feel her weight crushing my face I want her to ride my nose nonstop but she don't want do it with me I real want to live this fantasy with her but she feel weird couse she is older woman and don't want to sit on me even when I try to carry her like in romantic way she refuse she think couse she older and bigger then me I don't need to do this for her I really want to treat her like a queen and a queen need a face to sit on .
Sometime I think I should just find someone to experience my fantasy with them and be a seat to someone alse but I really want to her to try sit on my face
Anyone have a advise for me