Do I have a right to be concerned?!

I'm 23 & im my first serious relationship.. so I'm not really sure what I have a right to be concerned with & what's just my insecurities showing through. My boyfriend is going to a funeral for a coworkers parent that passed away. Which I think is very sweet of him. However, he's only going with one female coworker that's the same age as us & then they wanna go to dinner after together even though I am off today & can hang when he's done stopping by at the funeral, is thats out of line or am I over reacting?