re: If I start investing would it be better to dump a bunch of money all at once

Better to dump a large sum in on the front-end. Since you are just starting with investing, then investing in increments might not be a bad thing to do as you learn more about what you're investing in. It helped me early on to invest smaller amounts to break the ice and settle my nerves. There's enough doom and gloom on the internet/media to make you believe you'll lose all your money the day after you invest it. You might be more comfortable with spending in increments of $500 - $1000 at a time instead of $15,000 all at once.