> I live in the US since 8 years and still misunderstood it. in particular it's hard to tell whether you mean 'since I were eight years old' vs 'for a span of

> I live in the US since 8 years and still misunderstood it. in particular it's hard to tell whether you mean 'since I were eight years old' vs 'for a span of eight years' also, a native speaker would probably use tense such as "I have lived", so casually, "I've lived in the US for 8 years and still misunderstood it." and noone ever uses whom, but you probably used it correctly ps you typoed 'possibly be' and 'it'