I have A QUICK minute so wanted to offer my opinion here before i reply to my other posts :) I believe yes, there are older indigos but not as many as younger. If I remember correctly it is belived that the older ones came to help pave the way for the younger ones.
AS for the self confidence issue I would say if you fit all the other characteristics it is likely that you could be an indigo despite your concern here. I myself 100% believe I am an indigo (i am 25) as well as my 5 yr old daughter and i have self confidence issues now because of my past, my mother constantly putting me down over every little thing wore me down too in addition to the sexual abuise past. I think more of what the indigo desc is talking about is the inner confidence.. I am very insecure about , say , my physical appearance, however I have this inner confidence, as like I have always known that I was here for "a reason" believe it or not that is something a lot of people don't realize. I've always had a sort of self important mind but I never showed it because of my family life. In other words I would say I have always had this spiritual side way more than the other, I am not very grounded, every chakra test, "aura photo" or intuitive I've ever met/done says the same thing... I am not grounded, i am supposed to be in the healing field... my aura is green/teal and indigo...whatever you want to call the different descriptions, I think we all know what we are. When i heard the term indigo child it just resonated with me...like my soul recognized the term and felt so deeply connected. I just knew.. I think that is the self confidence it means...i believe a lot of indigos can lose the outer confidence because of how we are and the reaction of parents who didn't understand us and the labels we may have picked up such as ADD, ADHD, OCD,etc that could have reprogrammed us or trained us a bit intoforgetting our true selves. However I can honestly say that oddly enough even in my hardest times..say at age 14 when I was sexually abused, abandoned by my mother and put in foster care away from any family then emotionally abused and neglected there, while being in a relationship with a physically abuse boyfriend 4 years older than me .....even at that time I was at peace knowing that there was something bigger...and I just had to make it through...I can't really explain it but I hope you understand what I mean, it is not persay the same confidence one normally speaks of...others may even call it "cocky" "a legend in your own mind" self important, or some of the even more negative labels i already listed above. Trully it is just that you may remember your purpose a little clearer, sooner and easier then other people.
*Of course this is just my opinion and I also want to say that I do not believe indigos are anymore important than any other person or classification someone might fit into ( because we all probably fit into several) I believe that every single person's purpose is equally important as the next. no soul more special than the next.
I thank you for your support of me and I will email you directly more likely tomorrow as it is getting late. I hope i can somehow help you on your journey as well.
you can also email directly if you need anything