So I tried the Capital One check for upgrade link and it turns out i'm eligible to upgrade to the Quicksilver card from my Journey student card! My question is, if I wanted to go ahead with this upgrade, can I still use my Journey card up until my new Quicksilver card comes in? I use my credit card for everything so I don't want to be without one for a week if I don't have to be.
You'll be fine. The new terms will kick in almost immediately, and your current card will be good until you activate the new one.
And also, I was hoping to try for a credit line increase tomorrow after my statement closes. Is this upgrade going to affect my chances of being approved for a CLI?