Advise my family is not understanding!!?

me and my bro want to join swimming classes as we r having summer holidays..we have swimming experience there is a coach over there too but they don't allow us to go there..plus they don't even allow us to go in anearby park..i m 19 years old and my bro is 14..plus it's tym for my university nw as i m done with my high school but for uni one need to prepare for entry test even if u hve good grades and for entry test we have to go to other city..that other city is just at a drive of 2 hours away from here but my parenst are not letting me go there i donno y.. i tried to ask them a several times the reason for having restrictions upon us but thye neva give any satisfied answer..they even never reply to our answers and if we even say them we want to go outside they ignore us and often says that their children are mad..is saying them to let us go to university bad?is going to swimming bad?i tried to make them understand the things several times but they don't..plus they r very rich people not poor that they can't afford our studies..please give an advise