I wanted to be a police officer but when I grew up I didn't want to No it's not natural because I wanted to conflicts with I didn't want to. They would both need to have the time frame specified to make it work. Specify when you did want to be a police officer and it will work. For example: When I was 20 I wanted to be a police officer, but when I grew up I didn't want to. Recently I have wanted to be a police officer, but when I grew up I didn't want to.

I wanted to be a police officer but when I grew up I didn't want to. . sure. It's sort of ok, but not really comfortably natural. Other answers here immediately try to move it to a more natural way of saying it. But, it's not incorrect and quite understandable. . I once wanted to be a police officer but when I grew up I didn't want to. I once wanted to be a police officer but when I grew up I didn't. When small, I wanted to be a police officer but when I grew up I didn't. Or you can go more elaborate as suggested by others. . Can't agree that Recently I have wanted to be a police officer, but when I grew up I didn't want to. is natural. Recently I have wanted to be a police officer, but while growing up I didn't. - Seems ok, but turns your sentence meaning round.

"I wanted to be a police officer but when I grew up I didn't want to." Personally, I am confused about when you wanted and didn't want to. So I don't really know when these events took place. Try something like these: "When I was younger, I used to want to be a police officer, but now that I am grown, I no longer want to." ( I did when I was a child, but now I don't.) Or maybe you mean: "I have recently wanted to become a police officer, but when I was growing up I didn't want to." ( I do now, but when I was a child I didn't.) I hope that helps.