A. Yes, she can get her second (or third) MMR after 2 or 3 months. In fact, the second MMR can be given as soon as 1 month after the first one was given.
Unfortunately, this is a common situation that occurs as people move, change doctors, or simply lose their vaccine records. And in most cases, if you are unsure if your child received a vaccine, then it can be simply repeated. According to the American Academy of Pediatrics, 'no evidence indicates that administration of MMR, varicella, Hib, hepatitis B, or poliovirus vaccine to already immune recipients is harmful.'
If you really think that she got the first MMR shot, an alternative to giving her another one would be to ask your doctor to do a blood test to check her antibody levels against measles. If she has good levels, then she may not need another shot. The problem with this strategy is that if she has low levels of antibodies, then in addition to the stick for the blood test, then she will still need a shot.
You might also review her full medical records. It may be that even if they didn't record it on her vaccine schedule, they may have put it in the doctor's or nurse's notes.
The CDC provides this Catch-up Schedule for children who are behind on their vaccinations.
