Changing my sons name

We didn't have a name for our son the day we left the hospital, so we picked two we didn't mind and flipped a coin :( we literally couldn't agree. Now he's 4.5 months old and I'm so upset about it. His name just doesn't sit well with me and i cry over it. Is it too late to change it? Would you think badly of someone that did? 
Also, I know people will want to know the name to try to tell me it's fine and that the name is cute, and I appreciate that but I just still am not ok with it for some reason.