I have been trying for a baby for 3 months I have twin girls I got pregnant the first time of trying for my twins but this time it doesn't seem to be happening can't you help me by telling me is it normal for it to take time or is there somehing wrong with me

There is nothing wrong with you. The normal range and percentage is 85 % of couples conceive in about a year of trying.

If after a year of trying and no success then I would say make an appointment to check yourself out and your partner.