You're not alone. I immigrated to the US from Asia in the 90s. For many years I didn't understand spoken English fully. Arguably I still miss some words now and then, even nowadays, after over 20 years living in an English environment. I had great grades throughout high school and college here mostly thanks to having excellent reading and writing skills in English, since I came from a place in Asia that emphasized learning English since childhood. Listening to spoken English is not easy for non native speakers.