With the target time in place, the question of pacing strategy remains..
This is obviously individual. I believe that an even pacing strategy for non-professional runners works best. Professional runners tend to run faster the first half but this is quite a risky strategy for us common people.
Finally, for the first marathon it is worth considering a so called negative split, i.e. running the first half slower than the second half, allowing for a strong finish. This can be a key ingredient for making the first marathon attempt a positive experience, and reaching the finish line with a smile on your face.