I want to dye my hair back to ash brown but I have put high lights in it and it is strawberry blond. Will it turn my hair green?

If hair is in good condition it should not, especially with the red tones already in it. Red cuts Green and vice versa.

Green? No I don't think so. First, make sure you're is well conditioned before you do this... if it takes a while to get it in better shape, then do what's necessary and wait. But ash brown is a cool color. The red tones and strawberry blond that you have in your hair is on the warm side. So if ash brown is really what you want, make sure it states that it's a COOL shade to cancel out the red and get back to "ash".

I've made that mistake too often since my hair has natural red highlights in it and COOL hair dye colors are the only way to minimize them.

Yes I am the Queen of dying hair! Lol as long as you condition your hair youwill be fine! Just make sure you use a shade a little darker than your red. And if you are using box color make sure it's a quality brand some colors you can get away cheap but I would say when it comes to brown and red don't go to cheap.