Because you were smaller, the games just seemed so much bigger. You were amazed by everything you saw, so you took your time.
Now you're not only playing a game you already know, it's also a game that's incredibly simple by today's standards.
I have personally found that some games are harder now than when I was a kid. Super Mario Bros 3, the last world with all the battleships, tanks and firepits.
How did I ever beat that game as a 12 year old??