If you're looking to meet others in a safe, unintimidating environment, munches are a great place to start. A lot of AB/DL and ageplay munches are listed here:
LittlesMunch.com
There are also a lot of munches and local groups listed on Fetlife. Fetlife is a great site to join. It's for people of all sexual orientations, but most of the people you'll find there are straight. Keep in mind that Fetlife is supposed to be primarily a social network, not a dating site. Don't be too forward when you approach people.
If you're gay or bisexual, checkout rupadded.com, abdlc.com, and dl-boy.com. I think the first two of these sites are open to straight men and women too, but the gay male presence is strongest. dl-boy is for gay and bi men only.
Some safety tips, which you may have already heard, but just in case: If you're meeting someone in real life for the first time, always meet in a public place, such as a cafe or restaurant. Arrange your own transportation. Don't accept a ride from a stranger. I've met quite a few AB/DLs for coffee or a meal, and I've never had a "bad experience," but I still think it's a good idea to take a few sensible precautions.
Finally, think carefully before posting pictures that contain both your face and your diaper or obvious AB items to any of your online profiles. This is the age of Tumblr. Once pictures are posted on the Internet, they tend to get stolen and posted elsewhere.