Today I have a guest post from JT over at JustMakingCents.com. He writes about how he went from $15,000 in college loans to financially retiring in his 30s, drawing on lessons learned from over 15 years on Wall Street. He also shares his experience teaching his children about money. Enjoy!   Your kitchen looks great. You wiped that countertop down to a sparkling gem and picked the perfect Pandora station to play. Since your friends will be over in half an hour, you dial up your favorite takeout and order 5 large pizzas. After you order, you check how many…