My baby is head down at 31 weeks. Will I deliver early?
All in all, it is actually good that your baby is head first. While many babies destined to be head down at term are still breech at 31 weeks, a head-first baby at that point (especially in a first pregnancy) is unlikely to flip around. So this means you are less likely to be dealing with a "malpresentation," like breech or transverse lie, as you near your due date. But it does not mean anything about when you will deliver.
Signs of possible early delivery include frequent uterine contractions, pelvic pressure, or any bleeding. If any of those things develop, be sure to alert your doctor or midwife so she can make sure all is well.
Sounds like things are moving along for you! Good luck!