You say you can do 15. If you can do another here, I would do iron man 2. Ant Man is a personal fav, so I recommend it. But the story isn’t as important for the infinity saga. I would recommend to find a YouTube recap video for anything you skip.
• Watch- Iron Man 1 • Watch - Captain America 1: The first avenger • Skip - Iron Man 2 • Skip - THOR 1 • Watch - The Avengers 1
• Skip - Iron Man 3 • Skip - Thor 2: The Dark World
This is where the fun begins
• Watch - Guardians of the Galaxy: Vol 1 • Watch - Captain America 2: The Winter Soldier • Watch - Avengers 2: Age of Ultron • Skip - Ant Man 1 • Watch - Captain America 3: Civil War
• Watch - Dr. Strange 1 • Watch - Guardians of the Galaxy: Vol 2 • Watch - Spider-Man 1: Homecoming • Watch - Black Panther 1 • Watch - Thor 3: Ragnarok
• Watch - Avengers 3: Infinity War • Watch - Ant Man and the Wasp (Ant Man 2) • Skip - Captain Marvel 1 • Watch - Avengers 4: End Game • Epilogue (up to u) - Spider-Man 2: Far From Home