I'm 30 yrs old I have diabetes type2, and can diabetes affect my future pregnancy?

Yes. Type 2 is typically caused by obesity. Complications during pregnancy can arise and it is imperative that you maintain good glucose control throughout pregnancy. If related to weight, weight loss with good dieting prior to pregnancy can prove quite helpful.
Absolutely. When the mother is diabetic any pregnancy is automatically higher risk and needs to be managed very carefully. Start by having your diabetes well controlled prior to the time you become pregnant. Talk to your doctor about your plans to become pregnant well beforehand. During your pregnancy make sure to get to all of your pre-natal visits.