Guy trouble - Advice please !!!

So I have liked this guy for over a year now and he has liked me too. He is older (18) and I know I'm younger (15) but age doesn't really matter to my parents. Honestly - he can be amazing but he has done a few things wrong but he has stuck with me for a year even though I'm not allowed to date. He has asked me out numerous times and I keep on saying no cause my parents say no - my parents think I'm not ready to date but I feel ready... I have spoken to them and they finally let me go out on a double date with him but now I'm worried if he wants to get more serious and I can't because of my parents and than we will sadly have to end 😩 I really like him and I need advice to convince my parents to let me date him - go on dates alone as well - and possible be his girlfriend. Things between us have faded before but we are okayish now - not 100% because he wants to be with me but I can't do we don't know what to do😓 advice please