"I chose the USA because I love speaking English and am good at it"
It's for a past event, should it be "I loved....and was good..." instead (even though it's still true today)?
Either one of these seems fine, but the implications are a bit different.
I chose the USA because I love speaking English, and I'm good at it.
This implies to me that your feelings about English haven't changed.
I chose the USA because I loved speaking English, and I was good at it.
Whereas this implies that something has changed since then, or some other factor is more important; I would expect to see that usage in a context like this:
I chose the USA because I loved speaking English, and I was good at it, but now I miss hearing my native language.
(Note also that I would in both cases say "... and I am/I was good at it" instead of "... and am/was good at it").