My daughter is 30 days old and she pooped only day before yesterday afternoon. Is that a problem? Will tat be a constipation problem?

HOW'S HER APPETITE? If you newborn is not having regular stools it could be her diet. Are you feeding her foods other than her formula and how often? . Is she having any discomfort? When she has a stool is it soft? There are many factors which can constribute to contstipation. Check with your doctor.
Not a problem. Constipation is usually hard, difficult, and infrequent. Infants can be very variable but usually find a pattern. 6 or 8 times a day or every 3-5 days can be normal. You should talk to you doctor if the bm becomes difficult and/ or hard regardless of the frequency.
How fed???? A breast fed infant may stool a bit every feeding or an overflow diaper once a week. If it is soft it is not constipation. If formula fed, the pattern is more likely to be a few daily or at least every other day. If stools are soft & baby feeds well & plays, there is no reason to be concerned. If a poor feeder & not wetting diapers at least every 6 hours, I would have her checked.
Need to see a doctor. How frequent you daughter has bowel movement? Average people should have bowel movement 3-4 times per week. If less than that your daughter possible has constipation. The cause of constipation has many reasons. You better tell you daughter to check with her doctor.