Practicing introducing myself and have a few questions

(This isn’t for an academic assignment, don’t worry. I’m learning for fun)

1. How would I write my name (Parker)? Would I write it as パーカー or as パッカ?

2. Would I write “I am an American student” as “私はアメリカジンがくせいです”?

I’m very, very much a beginner so any tips would be greatly appreciated. Thanks!