If you have a ticket for Avengers-Endgame, be stoked. Be very stoked. It doesn't matter if you have an acute understanding of the entire thread of the Marvel Universe or if you're just a casual watcher of a few of the films, you're gonna love this movie.
The wife and I made it a day-date in the City and had a chance to watch it at the pristine and amazing Dolby Theater on Market Street in SF and it was such a great experience. They jam a TON into the 3-hour extravaganza: open storylines are wrapped up, there are like a bajillion superstar cameos(if you've been seeing the twitter rumors of "hey, this person might be in it," they probably are), and you are taken on a rollercoaster ride of emotions. I laughed, I was shocked, and yes, I even cried at the end. Like, real tears. I know, so emo.
I'll give you the ONE spoiler (non-spoiler) that they told us at the beginning of our screening. There are no exit credits at the end. Once the credits roll, you can bail(you're welcome for those ten minutes back).
Honestly, I never know how to write these things because I don't want to accidentally spoil ANYTHING for you. Go see Avengers-Endgame because it's a GREAT ride, ALL of your heroes will be there, and a lot of your questions will be answered.
PS...go see it in the highest fidelity possible (ie IMAX). It really is worth it.