Did Anne Frank go into hiding at the age 10?

No, Anne Frank went into hiding when she was 13 years old. Her family moved into the secret annex only weeks after her birthday on 12 July 1942. They had moved in weeks before they had planed since Margot Frank had gotten a call-up from Central Office for Jewish Emigration ordering her to report for relocation to a work camp. The family didn't want to send Margot away to her death so they moved into the secret annex on 6 July 1942. They were joined a week later by the van Pels family and later in November by Fritz Pfeffer. They lived there for 2 years and one month (Or 25 months) before they were found by a German police on 4 August 1944.