No credit card required
Browse credit cards from a variety of issuers to see if there's a better card for you.
Are you 1099 or W2?
Do you have a lender yet? If not, then contact several and ask them that question as it is a little bit different than a typical W-2 type income.
Pretty much the entirety of the mortgage universe can underwrite either on 30 days worth of paystubs for standard W2, or 2 years tax returns for anything else.
Long as the IRS knows about that income, don't sweat it, you'll be fine with 2 years history on that.
Don't know on January markets: going to be very local dependent but it's something of a frenzy right now with Yellen's latest word at least around here... my RE is pulling his non-existent hair out with everyone beating down his door over a .25% rate worry. California is admittedly more buy and hold with the way Prop 13 works though, not everywhere is like that.