[PINKY47]

Hi,

It looks fine to me but as you pinted out, some peaple may think there are too much 'desu' or sentenses are too simple.
You can change as follows;

Watashi wa Amerikajin desu. => Watashi wa America kara kimashita.
You can say like this if you speak outside of US.

Daigaku __ desu. => __ Daigaku ni kayotte imasu.

Watashi wa (age desu. senkoo wa (major) desu. =>
Watashi wa (age desu. __ (major) o senko shite imasu.

Yoroshiko => typo? Yoroshiku

Good luck!
PINKY47