Nope.

Power is force times distance divided by time.

This is important, because it just means it will take you longer to get up that hill at lower power. Also keep in mind that because it is pedal assist, it is augmenting what you are already putting into it.

My wife can climb a 22% grade in Eco mode. She isn't a lot faster than me on a non-ebike, but is much more well-rested at the top. You will be fine.