Thanks for your query
You will have to do many investigations to see that every thing is OK including ovulation confirmation, tubal patency confirmation, husband's semen analysis
etc. In your case age is a important factor as ovarian reserve
decreases with increasing age. Irregular periods
are common in premenopausal period.However some tests may be required for to diagnose the exact etiology like USG, D and C etc. I will suggest you to consult a good infertility
Best of luck and take care...