Made my Paypal when I was underaged...

Long story short, I made my Paypal about 5 years ago when I was under the age of 18. My only question here is that going to cause me problems when I start using Paypal to sell? I am over the age of 18 now.

Here is a piece from their Terms of Service -

"2.1 Eligibility. To be eligible to use the Services, you must be at least 18 years old and a resident of Canada at the time you open the Account. This Agreement applies only to Accounts opened at paypal.ca. "

I feel like I might be SOL

I have not tried this, but you can try editing profile information and then closing the account. Then after few days open account with real info (your date of birth).
You can also put address of someone you know if you want to be extra safe and don't put same address as before.

I would recommend opening a bank account and Paypal just for your business which is something you should do anyway.

What you did in the past will not matter but when PP runs your credit (if you start selling in any quantity) the question will become whether your dob and other info match what they pull for you from a credit bureau. I assume this is a real account in your real name. If you have no credit at all (a ghost) you may get shut down. Also obviously if they determine that you are a fictitious person you will be shut down. I'm not the expert on this just repeating what I learned from Modeeworld.

Don't tell them that you made underaged. I did and they banned my account permanently.