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.