I don’t remember since I’ve been going to places locally and around since I was young, but my first place at a natural habitat (that sounds so much cooler than forest right?) would be Sanjay Gandhi National Park. That place is like a retreat place for me at times and it’s relatively near where I live.
Well basically Mumbai being a city comprising of seven islands, is within a forest itself. And can’t choose one over the other, spending time in either too much would drive me nuts though practically surviving in the city is more feasible don’t you think?