Originally Posted by 2MuchMark

NoooOOooo.... if you do, you'll be lost.

If you can, you should watch all of these movies in order:

Phase One
1.1 Iron Man (2008)
1.2 The Incredible Hulk (2008)
1.3 Iron Man 2 (2010)
1.4 Thor (2011)
1.5 Captain America: The First Avenger (2011) <<<<<<<
1.6 Marvel's The Avengers (2012) <<<<<<<<
2 Phase Two
2.1 Iron Man 3 (2013)
2.2 Thor: The Dark World (2013)
2.3 Captain America: The Winter Soldier (2014) <<<<<<<
2.4 Guardians of the Galaxy (2014)
2.5 Avengers: Age of Ultron (2015)
2.6 Ant-Man (2015) <<<<<<<<
3 Phase Three
3.1 Captain America: Civil War (2016) <<<<<<<<<<<
3.2 Doctor Strange (2016) <<<<<<<<<<<<
3.3 Guardians of the Galaxy Vol. 2 (2017)
3.4 Spider-Man: Homecoming (2017)
3.5 Thor: Ragnarok (2017)
3.6 Black Panther (2018) <<<<<<<<
3.7 Avengers: Infinity War (2018)

If you can't watch them all, consider watching the movies I highlighted with <<<<<<<

And if that's too many movies too, then at least watch the Captain America movies.