The Dutch centre-back completed a £41m transfer to City from Bournemouth in July.
And after four years in the top-flight with the Cherries, the former Chelsea youth insists he has already showed he can compete at the top level.
Ake told The Mirror: "I have not signed for City thinking I can prove all the critics wrong. I have already proved to myself that I have the ability to play at top level – and I love a challenge.
"I have had to work incredibly hard to make it to the top – and I know I am ready. I have also achieved my dream of playing for Holland."
The 25-year-old added that he was excited to work with Pep Guardiola.
"I had to pinch myself in the arm. I was thinking, 'Is this real?'' Ake added.
"When I heard they wanted me to come to Manchester I was bowled over.
"I had a really good talk with Guardiola and there was an instant connection. The way City play really suits me. I have played against them so many times and I know how hard it is to face them."