I'm not really sure. I would have gotten both in 1995. I
probably
played Yoshi's Island first.
On the best sick day ever, I stayed home from school and beat Super Mario Bros. 2. Later that night, when I was feeling better, I went to the store and my mom bought me Yoshi's Island.
Since Super Mario All-Stars + Super Mario World came with my SNES, I would have beaten Super Mario World, Super Mario Bros. 3, and Super Mario Bros. 2 within a relatively short time frame. Oddly enough, I didn't beat Super Mario Bros. 1 until a year or two later.
I do remember reading the instruction manual for Super Metroid and thinking, "Samus is a girl...? That's pretty cool." Come to think of it, that was probably the first game with a female lead that I ever played to competion.