if you learn a language under the age of 4 you are native, 4-8 fluent/competent, after that you can never be native, so....do the best you can, and that can easily approach fluent
I learned French for family reasons, not so different from you.
The most important step for me was to realise that if i could ask for a beer, a direction, buy clothes or whatever, that i was already speaking French. After that it was just a matter of not panicking, explaining that I am english...