Well majority of the cases are like that only, majority of the third molars have curved roots and the nerve is always below it.
Next Steps
You should get an OPG first, thats the first step towards the surgical extraction of that third molar. And we do not leave the roots of the third molars inside the bone, get the complete toot, crown along with the roots extracted, with little bit of bone cutting, which is advised in cases like this. Surgical third molar removal is costly. Consult ur concerned Dentist. He/She might help you.