I’m going to both agree and disagree with everyone else. 😉
First, ignore those who tell you that you don’t need….even worse, shouldn’t have….a time goal for your first marathon, especially if not having one leaves you feeling rudderless. These folks are usually saying, “Your goal just should be to finish.” Well, duh! Who puts in the many weeks of training and goes to the start of a marathon without intending to finish?
Without a time goal, it is virtually impossible to have a race plan. And why put all the work into training for a marathon, then step up to the start with no idea of how you will control the race? You have only two choices at that point, and both are undesireable. You can stay very conservative and probably run a much slower time than you might have, then all you can say that you did the minimum and finished. Or, more likely, you will run what “feels” like the right pace which will almost certainly be too fast in the early miles, because of your freshness from your taper and race day excitement and adrenalin flow, and will lead to a bad finish….maybe even a hard crash and “survival shuffle” finish. Either choice is cheating all of the hard work you did to get ready for the big event.
A few folks who replied to you implied that it is especially difficult for a first time marathoner to determine a realistic time goal simply because they have no experience base to draw on. That is true. First time marathoners frequently set a time goal, then fail to achieve it. But that doesn’t mean you shouldn’t have one. As Ryan said, you, as a first timer, should simply make sure that your goal is a bit more conservative than more experienced marathoners might set.
Actually, I recommend that all marathoners set not a single goal…..but three goals. One is a “realistic” goal. In the case of a marathon, it is primarily based on a shorter distance race run within 4-5 weeks of marathon day. A second goal is what I call the “floor” goal, which is the minimum that one would be satisfied with….for a first marathon, that could be to simply finish. The third goal, which I call the “ceiling” goal, is the best that one might hope to do if everything goes well. (Some people call those last two goals, “pessimistic” and “optimistic” goals.) That establishes a range of success that allows for many variables that occur with every marathon….and other races….that you run, as opposed to just going with one “do-or-die” goal. A race plan is then based on the realistic goal and adjustments are made toward either the floor or ceiling goals as the race progresses, based on how you feel. It’s the method that I have used for all but my first of 21 marathons when I didn’t know better. (BTW, for my first marathon I did set a single goal of under 4-hours…..and ran 3:47:30. I got lucky. 🙂 ) I recommend that you set three goals.
Assuming that you set a floor goal of simply to finish, then how do you determine your realistic and ceiling time goals. I have a couple of suggestions.
Base your ceiling goal on what a running calculator says that you should be capable of running based on previous races…..ideally a 10k-half marathon race run within a few weeks of your marathon. That’s about the best that most first timers, and many experienced marathoners, can hope to do. Except for very advanced runners, race calculators tend to be overly optimistic because they assume that you are optimally trained for the distance. Most first timers….and many experienced….marathoners aren’t.
Arriving at a truly realistic goal requires finding a way to adjust from the prediction of a running calculator. That’s tough to do because there are so many variables. You could just quess or swag it. However, there is a more systematic way. It’s a method that, based on inputs from others, I devised and described in a post on RWOL a few years ago. Several runners who use it have told me that it more accurately predicts their marathon potential than simply relying on the running calculator prediction. Rather than repeat it here, because it is very long, I don’t think Ryan would mind if I refer you to where it is archived on my Running Page. It’s a post titled, “Predicting A Marathon Time” near the bottom of the Marathoning section at http://users.erols.com/jimsue/running/jim2%27s_running_page.htm
Good luck in your first marathon!!!