MabiPro: The Authentic Old-School Mabinogi Experience

I was wondering if it's possible to set the hotkeys to use the number keys instead of the Fn keys. I have to click my Fn key in order to use the hotkey which makes it harder to click skills fast. If there's any way to change them so that I can use number keys like in the official version that would be really helpful.

Well yes and no.
No there is no way to swap the F1-12 hotkeys.
However, if you open the Skills menu, you will notice that the first 9 skills are numbered 1-9. Pressing the corresponding number key will use the skill in that slot by default (these hotkeys can even be rebound in options). And you can set different skills into these slots using the different sections of the skills window.
Using Ctrl+ a number key, you can quickly swap which skill-set you have selected in the skills window also.

Hard-ish to explain clearly, but just try putting Defend at the top of your skill window, then press 1 and your character should load Defend.
I should stress it is specifically the number ROW, and not the number PAD on the right-side of your keyboard.
I have a laptop I use sometimes with the same issue as yours, and it is very annoying indeed.