To be honest, with the right amount of commitment in the initial stages, it is pretty easy. My native tongue is Urdu and I can say, without any doubt, that my English is MUCH better than my Urdu. It's odd how the brain works, but I would say it's mostly because I think and speak, whenever possible, in English (especially on the internet). So I would say it would not be as difficult as you may think. Just remember, nothing is too difficult to learn! And the more you know the better!