My faint line turned into BFP!

Cara • Expecting our first baby Jan 1st 2016! Married my best friend after 8 years together 10/10/14.
I had a faint line last Thursday and now it's darker than the test line. I got the faint line at 8DPO. I'm now about 4 weeks prenant. First doctors appointment May 20th and due date is January 1st! :-)