Some of the best aikidoka in the world that I ahve seen are from Japan. Japanese women are typically smaller than American women. They have to rely almost solely on technique rather than strength with demonstrates aikido's effectiveness.
However, being stronger is only a plus, you just have to learn to differentiate between when it is your technique doing the throwing and when you are using muscle. Otherwise, you will not hone down your technique. You should use your strength in aikido but you should not find yourself having to muscle you way through a technique. If that is the case, you aren't performing it right.
I am very strong and being strong is an advantage. It is there when you need it. Nothing wrong with that!