I'm in agreeance with the other commenters in that you should really evaluate if your friends/family actually need to know about your little-ness. I can understand both sides though.
On one end, if you tell them that you're a little and they are accepting of it then you're more free to express yourself. You have less worry about hiding things like sippy cups or pacifiers. You may also be able to come to them for more specific advice that may pertain to you being little.
On the other end, if you don't tell them then you can keep it a special secret for only a very select few individuals (like partners) to share with you. Your private life remains private and you don't have to worry about any one talking about it behind your back or judging you. You also don't have to answer questions they may have about being a little if you were to have told them and brought it to their attention.
I, personally, wish I was able to tell my family members because, I think, they would have be a better idea of my emotional state at times. They would also have a little more information about my interests. It feels daunting to tell someone though because there is so much that goes in to it.
Nonetheless, the site here has a pretty decent article outlining how to prepare and what to prepare with if you're going to come out of the toy box. I'll link it below in case you haven't see it yet, because I think it encompasses some really important points:
http://www.littlespaceonline.com/app.php/page/comingout
It pretty much covers anything I would have said. Be prepared. Be prepared for a lot of questions. Be prepared with specific information. Be prepared for good and bad responses. Be prepared for the best and the worst. Be prepared for them to be very quiet, but also be prepared for them to jump up and want to discuss it immediately.