Can i still have a normal delivery even if i have chocolate cyst? how high is the risk that the cyst may rupture during labor contractions?

Labor and cyst: There should be very little concern of a cyst rupturing during labor. I am not sure how you know that you have a "chocolate cyst" and i don't know how large it is therefore i can't give you a complete answer. I am impressed that you were able to get pregnant with a chocolate cyst aka endometrioma present. Short answer it should have no impact on your ability to deliver naturally.

Yes and low risk: Pregnancy is actually sort of a hiatus for the endometriosis process. Once pregnant, the presence of a chocolate cyst (e.g. Endometrioma) does not affect your ability to undergo a tol (trial of labor) and achieve a vaginal delivery. Cysts of this nature are quite tenacious and unlikely to be affected, certainly to the point of rupture, by labor contractions.