In theory, your fertility should return to normal just after your first period off the pill. Your reproductive endocrine system should re-set without any problem and you should ovulate on your next cycle. This is especially true for the birth control
pills today that have very low levels of estrogen and progesterone - like hormones. Some women do report some irregularity to their cycles after stopping birth control. This irregularity may represent some cycles in which ovulation does not happen and thus, conception cannot occur. You can be fairly sure that once your cycles are regular again, that your fertility is back to what it was before you started the pill.
If you are trying to get pregnant now, then you should schedule an appointment with your OBGYN. You can discuss methods to increase your likelihood of conceiving (when to have intercourse etc). You can also start taking prenatal vitamins which are helpful to your baby in the first 6 weeks of life when you may not even know that you are pregnant. Keep in mind that statistically you won't conceive the first month or two anyway. If that happens, don't let that frustrate you. Your doctor
will want you to have unprotected intercourse for at least a year before any tests of infertility will be done.