How Much Will My Car Insurance Be?

I live in Dallas Texas, I’m 18 years old, I’ve had defensive driving school, which I’ve been told gives you at the most 10% off your rate…i own a 1998 Jeep Grand Cherokee Laredo, in REALLY good condition, car alarm…all the gadgets…but since I’m 18 who would be the best to go with…also I’m seeking FULL Coverage for the first 6 months of driving in Dallas, because people do not know how to drive and I want to make sure I’m covered…any help or advice???
THANX