Even supportive parents can have difficulty with this. They may feel that you are rushing things. At least that was whatI observed with a good friend of mine. She, thankfully has come around completely, and last year her son got married to his long time girlfriend. And the whole family celebrated it together.
I can’t really advise more than others here have. It may help to talk to a counselor, or find a support group of others in the same boat. Good luck.