I’m new, but do I just suck?

I'm new too Pokémon's tcg trading card game, but decided to download the pocket app after a friend mentioning it 2 days ago. I pulled a couple good cards I guess, getting the venasaur ex card and and tried building a grass based deck. I don't have many support cards except the ones the game gives you to start off with, and have to fill the rest of the deck with normal types. And let me tell you how infuriating the RNG of the game could get. Out of all the matches I've gotten I won only 2 and lost the rest, due to me not being able to do a single damage to the opponent because the coin flips I always get are double tails or the cards I'm trying to build my strategy off of don't show up at all and it makes me scramble. It's getting really infuriating. Do I just suck? Do I need to get more support cards? Or do I need to just rebuild the deck entirely.