I grew up in an immigrant community. I was born in Puerto Rico, but my mother was Brazilian. My mother never did learn much English. It was a very frustrating language for her. I learned English from watching cartoons and television, but missed much of my first and second grade years, because I didn’t understand a word that the teacher said. My children speak three languages, but only want to speak English. They rarely even tell others that they speak another language. This process is pretty consistent through all the immigrant communities I have been in. The adults don’t always assimilate, but the children almost always do. The bottom line is that children that grow up in the US, want to be completely American, whether their parents do or not.
When my great grandfather arrived in the US from Wales in 1863, he sought out the Welsh community in Pennsylvania. The young lady he was courting was from Aberystwyth. He joined the Union army to gain her father's approval. Boot camp was held on the train enroute to the front lines. His unit was captured within days and he spent most of the war as a POW. At the end of the war, he returned to Pennsylvania and married my great grandmother. They insisted that their children speak only English. All 19 of them. It's a shame because the number of Welsh speakers in the world is small. All of the children were very successful. Most graduated from college and pursued engineering or farming.
Kudos to you for becoming fluent in English and bringing up your kids with the gift of multiple languages.