It is impossible to say for sure since the movie has not been released yet, but a lot of fans are saying they are very excited to see it and some are even planning group showings on opening day. The amount of money that people spend to see the movie over the first weekend after the release will dictate how well it does in the box office.
Marvel is very well known as one of the best movie producing companies around right now. The movies usually gross a lot of money and always seem to leave fans wanting to see more of their favorite commic book heroes on the big screen.