Hello, I have gone through your query and understood the concern. If you have always had regular cycles, your age of pregnancy can be approximately calculated even though you had a recent irregular period excluding the number of days your period got delayed. The ideal way to estimate the gestation age in the current scenario, however, is to get a trans-vaginal sonogram. This gives you the location of the gestation sac, the fetal pole, cardiac activity and so on with more accuracy. Follow up gives you good concurrence. Hope this helps.