This is the right time to see the endocrynologist. Since irregular periods
are present and Obese
people commonly have insulin
resistence or some times hypothyiodism which can be diagnosed by blood tests and treated with medications. It would be better to rule out these conditions, if they are not present then it would be lot easier to concieve.
Using ovulation prediction
kit AND REDUCING WEIGHT would be a good idea for conception
also consult a Gyne before you start triying concieve
Hope this helps