Ever since I found Islam I knew its the one for me. However I keep asking my mum if I can be muslim. She says no. I am 21 now. I know islam says to respect one’s mother. Am I disrespecting my mother by being a part of Islam, reading quran etc?

My dear daughter. You do not need their approval
There is no obedience to a creature in what angers the Creator.
It is obligatory to obey parents in what does not conflict with the commands of God Almighty.
If the demands of the parents conflict with the commands of God, it is not permissible to obey them.
The Almighty said in the Noble Qur’an (But if they endeavor to make you associate with Me that of which you have no knowledge,[1161] do not obey them but accompany them in [this] world with appropriate kindness)