I did rejected my best friend

First time we meet since grade 9 and he confess when we were grade 10. Its just happen quickly I really didn't expect him to do that. Now I realize he is one of the nicest guy I meet and be friend with. If he has a girlfriend now she will be the luckest girl in the world, I'm not saying I regret saying no because I really don't want to be in a relationship yet I want to have a FREAKIN job and help my parents first. Even though he told me he could wait, like he really insisted like how nice is that but if you guys think of it for a second, it would be a waste if I said yes he could wait for me but what if he find his true love and that's not me and what if I find my true love and yet I can't be with the one because I have someone I promised to wait see? It will both hurt us so maybe just maybe I did one of the greatest decision of my life ehehehehe. By the way we are back being friends even though it was awkward at first