I am a complete beginner and have the 199x D&D "New Easy To Master" beginner game and I'm trying to learn 5e. Would it still be beneficial to play through this learning card adventure game for experience or might the rules mislead/confuse me as to what I need to know now? I think this is a 2e set. I just picked up the New Starter Set for 5e and have been reading the rules for that but have the older game on hand I bought back in the day and never got around to learning.
The games are completely different and it would only mislead you. At most, you could get some flavour from the old 2e set, but enough has changed that even for flavour it would hinder as much as it would help.
The new Starter Set is a very good introduction to 5e though, so there's no additional benefit you could extract from the old set anyway. Stick with the new Starter Set, and save the 2e set for revisiting the past state of the game, if at all, once you feel well grounded well enough in 5e that it won't muddy the water.