I was diagnosed at age 4 and also feared becoming pregnant, because I didn't want to pass diabetes on to a new generation and I worried about pregnancy induced complications for me.
Turns out I shouldn't have worried. I had a completely healthy pregnancy at age 32 and have had no complications. My son is 6 now and is not diabetic. Statistically he has only a 2% chance of developing diabetes, which is much lower than I imagined.
If you have good health insurance, an insulin pump, and a cool OB-GYN there's no reason you can't have a healthy pregnancy. My A1c was around 6.9, but once I knew I was expecting I set a target blood sugar of 80 and tested often to make sure I didn't have lows. My goal was to have a non-diabetic A1c and I achieved that with a 5.1. I ate what I wanted (had a thing for mint chocolate chip ice cream cones) but made sure to carb count carefully and test an hour after eating, to give an additional bolus if needed.
There are many diabetic moms out there. Cheryl Alkon's book about managing pregnancy with pre-existing diabetes is a great resource.
Take any diabetes pregnancy statistics with a grain of salt. Think many of these research studies were conducted before insulin pumps made tight control possible, or they include diabetic moms who are totally out of control. I'm nothing special and have a relaxed attitude with my D management, but was able to do be a healthy diabetic mom. I worked right up until the end and felt great. My son was born healthy, with a normal blood sugar.
You can totally be a mom if you want to be.