Androgenic alopecia is not a disease with a cure but an accelerated ageing process which needs to be treated with a maintenance program including Minoxidil. I can understand that when you are 21 years old it can be quite stressful to imagine using a medicine long term. However if you use this regularly you will be able to maintain the existing hairline. treatments such as PRP are showing promise in rejuvenation of hair. Later you can plan for a staged hair transplant.
Remember in hair loss, prevention is always better than cure