I had chlamydia at 16 now I want a baby can I get pregnant

Most likely yes, that is between you and your doctor.

But why would you want a baby at 18?
You should be getting education
Getting a better job
Sitting up for a better life for a child.

Are you or the taxpayers going to be paying for this baby for the next 18 years?
Sorry to be catty. Yell at me if you have a good career going, or a rich husband, to support you and a helpless, needy, money-guzzling child.