“Aficionado” is a generic word for the things one likes. E.g. Pepe es muy aficionado a los deportes, a la montaña, a la lectura. It´s also used when you do something in a non professional way, kind of amateur. But, when you speak of a certain fan of a sport team, you use the word “hincha”; and when you speak about a group of music, you use “fan”: “es fan de los Beatles”. Don´t ask me why!
"Hincha" is more for sports and has more of the idea of "supporter", whereas "aficionado" could be used, but could also be understood as an amateur player, rather than just an observer. The most important issue, is that the TENSE (not "time") should be present in Spanish, because the action is still going on. We use the present perfect for this in English, but not in Spanish.
The options I can think of are:
¿ Desde cuándo eres hincha de Penn State?
¿Cuánto tiempo hace que eres hincha de Penn state?
¿Cuánto tiempo llevas siendo hincha de Penn state?.....I think this last example would be understood, but I don't like its style, sin.ce we are talking about ONE ELONGATED/CONTINUOUS action, rather than a repeated one. However in the following example it sounds better: "Cuánto tiempo llevas yendo al gimnasio?"=How long have you been going to the gym? (you go daily but in the meantime you do other things).
I hope my comments have been of help, and not more confusing for you