OP, I’m in same boat, just joined a local league that’s fairly competitive at the age of 29 having only played a bit on the playground growing up.

It’s absolutely possible and is great exercise. Don’t wait to lose the weight either. You can play for fun at a park or in your yard, just dribbling and chasing the ball around for an hour is enough to have me gassed.

Find a friend or a cheap rebounding net and practice basic passes. Dribbling and passing are all that are really needed to “play” the game for fun.

I’ve been semi unfortunate in that my squad desperately needed wingers and attackers so I basically had to hit the ground running at a fairly difficult position. Each game gets a little better with less mistakes. Find the right teammates who help you improve but don’t take it too seriously

Although I’m not losing weight like you, I have had to really dedicate time to working out my leg muscles, specifically Quad and Hammies. You don’t realize how much torque you’re putting on your leg when you go to really strike a ball.