There is no need to create gymnasiums for yourself; your Being is in charge of that. It is better to instead turn your time into benefit for others: rather than focusing on yourself, find ways to help other people. Get out of the house, volunteer somewhere, help alleviate the suffering of others. You will learn far more from this than anything else you can do.
Regarding sex, again rely on your Being to handle that for you. None of us know what kind of time we have, so rather then rushing into self-made situations, it is better to restrain our impulses and reflect on our desires. There is no need to rush into sexuality; in fact, I would advise to wait as long as you can. Take advantage of your youth and single status, and convert your time, energy, and enthusiasm into service for others. When your Being wants you to become sexually active, that situation will present itself, and you will have a whole new set of problems to deal with.