When landing, who has right of way?

The landing rule

14 CFR 91.113(g) covers landing. When two or more aircraft are approaching an airport to land, the aircraft at the lower altitude has the right-of-way. In this scenario, the large airplane is below you, so it has the right-of-way.

The lower aircraft can't cut in

The same paragraph limits the lower aircraft. It can't use the rule to cut in front of an aircraft that's already on final, or to overtake it. Being lower only gives you the right-of-way until someone is established on final.

Size, category and the aircraft on the right

Size isn't part of the right-of-way rules. The category order (balloon, then glider, then airship, then airplane) decides between different categories of aircraft, and both aircraft here are airplanes. The aircraft-on-the-right rule in 91.113(d) is for aircraft of the same category converging at about the same altitude. Landing has its own paragraph, and it takes precedence.

Emergencies and towered airports

An aircraft in distress has the right-of-way over all other traffic (91.113(c)). At a towered airport, the tower sets the landing sequence and you follow its instructions, but you're still responsible for seeing and avoiding other aircraft (91.113(b)).

The large airplane's wake

The large airplane has the right-of-way, and it also leaves a powerful wake. Following it to the same runway, stay at or above its final approach path, note where it touches down, and land beyond that point (AIM 7-4-6).