Do you think Lady Igraine was wrong to keep Arthur’s identity a secret from him?

In context, Lady Igraine didn't have much of a choice. Uther had made the deal with Merlin that required him to give up his first born son, and Igraine did as she was asked. All parties believed that Arthur would be safer with Merlin, and when Uther dies as a result of poisoning soon after, the reader has to agree. As Uther's heir, he would have been a target.