/ Learning Polish but not focusing on the grammar, good idea?
Starting to sound like the chicken-egg argument.
I have several friends in the United States who are from Poland and are only slightly younger than myself. Though they have lived here and are now citizens they do not speak the king's English. Sometimes they make a statement that sounds more like a question, because they are in some way asking if they said it correctly. I let them know that I understood exactly what they were saying and then offer a better choice of words or sentence structure. What I read seems to be true. They are more interested in their English than in my Polish.
I understand all of the suggestions offered for learning so I'll move on to motivation so there is an understanding where I am coming from.
A few years back at the tender age of 64 we purchased an apartment in Krakow. We have visited many cities but for several reasons we chose Krakow. We wanted to travel Europe without the burden of having to return to the USA after only two or three weeks. Relocating to Poland was the best solution considering my wife's eligibility for citizenship and her being a fluent speaker.
Though language is certainly the most important item on the plate, I am also familiarizing myself with Polish history and culture from the middle ages to modern day.
I have seen advertised many Polish language courses and will get (need) help when I'm there selecting the right one for me.