Innocence, by my personal definition, requires not having made choices based on personal gain or greed in general.
As soon as yeu've ever made any choice of any kind with any sort of conscious decision, however, yeu're no longer innocent, and pretty much never will be again as all decisions, at some level, stem from greed.
That being said, as soon as a baby demands milk from it's mother, it's asking her to give up part of her own nutrition and self for the child's own benefit with the only benefit returned being that they'll stop crying; if yeu did this elsewhere in life, with the same situation of doing something bad and accepting payment to stop, well... "Extortion: Illegal use of one's official position or powers to obtain property", using the position of "I'm yeur child" to get food, which's described as personal property.
Sure yeu're legally required to provide such until they're 18, but still!
The decision process itself has already begun with the "Mememememe!" mentality. Everyone gives stuff TO me, I need not return anything back. This isn't innocence, but rather quite the opposite.
Which leads us to the concept... when does it stop being 'innocence' and become criminal? The difference seems to lie primarily in the individual's capacity for reason. If they can consciously make the decision to do so, then they are no longer innocent. Therefore, any human being who has developed enough to actually think, has already lost their innocence by default.
"Zomg yeu killed those innocent bystanders!" pft no they were hardly innocent; they may not've done a crime befitting that particular punishment, but they were guilty of SOMETHING. Note that even THOUGHT was once punishable by death; guilty thoughts, such as coveting something someone else has... is actually a major sin in biblical terms. And technically still applies, though not legally anymore. Amusingly enough, yeu used to actually not be allowed to have a man marry any woman if that woman was not the ONLY person he'd EVER had any naughty thoughts about EVER. Yeu can see how well that was enforced considering the species didn't go extinct in 3 generations with a zero birthrate. >.>;
In any case, noone's innocent. If yeu can think, yeu've already failed the test; however, yeu can still be innocent of particular charges or allegations, just not "pure" 100% of the time.