Projects going over schedule are, uh, not exactly an uncommon occurrence. In fact if you've been honest with your manager about your level of skill (as you said

Projects going over schedule are, uh, not exactly an uncommon occurrence. In fact if you've been honest with your manager about your level of skill (as you said in another comment) and assuming you've been keeping him up to date with progress and he hasn't done anything to get the project back on track (like getting you a mentor to work with), then it's really more his responsibility than yours if you don't finish. (That's not to say he's doing it wrong - this may be a deliberate strategy on his part; it's obviously not a life-or-death project.) On the other hand, if you wait until the last day before announcing that you're only 60% done, that is your responsibility. Don't be that guy. You should be talking to your manager now about how far along you are and what is an achievable state to leave the project in for somebody else to pick up (actually you should have started this some time back if you haven't already). e.g. you mentioned a lot of work went into gathering requirements - if you are not going to finish the project then that work probably needs to be captured. Communication is the key, and that's got nothing to do with whether you're doing coding or marketing. Nobody is going to make any inferences about your marketing abilities from your coding abilities or vice-versa, but if you prove yourself incapable of communicating with your team in either placement then, well, that would be the time to start getting worried. Failure is not always bad, but trying to cover up failure always leads to very, very bad things and it never, ever works. Remember that and you'll be fine.