Vacpress - when I was about your age (seems a while) in the sign shop we used a hooked knife to round over the edge of plex - but that was scary too! Also a wheel (sanding disk) hand held on a drill or belt sander - but then again on a sign 40 feet++ in the air you never notice the small imperfections.
I have seen flame-ploished and "melted edges" on some plastics - but control of the heat is important so you don't "flame" the project.
Maybe a beat up iron from goodwill/sallys?
Progress is amazing! Keep it up!
cheers - Jim