Lewis Carroll had many friends who were children. From the Liddell sisters in the 1850s, to Enid Stevens in the 1890s, these children brought warmth and companionship to his life and inspired his creativity. But the real story of Carroll and his 'child-friends' is a lot more complex than the famous legend of the gentle pedophile and his little love-objects. In fact it's been estimated that at any one time anything from 30 to 90% of his "child-friends" were actually late teenagers or adult women.
Carroll invented the now famous term "child-friend", but he used it in what was possibly a delberately confusing way, to refer not just to genuine children, but also to some woman-friends as well. Possibly he did this to conceal the fact he was associating with women old enough to create scandal (see the Victorian Child Cult for why associating with children was considered 'innocent' by Victorians). Combined with Collingwood's biography this confusing terminology helped create the illusion that Carroll only associated with children, which led in turn to the idea he was pedophilic.
In reality, a "child-friend" was any female of almost any age — at least under forty — whom Carroll especially loved. Some were little girls, some began as such but grew up and were still "child-friends" at twenty or thirty; but a substantial number didn't even meet Carroll until they were young women.