He is right about the credit score. It's not really relevant to you personally, unless you are trying to determine if you should refinance now.
However, it is worthwhile to check your three credit reports, using the URL that has been cited above. Review those reports and determine if there are any inaccuracies. You should deal with them before you start any refinancing.
If your current mortgage was resold after you originally got it, there's a good chance that your credit report will have entries for both of them. And, the first one won't necessarily reflect that the account was paid in full. Unless someone looks at it closely, it will appear that you are making two (or more) identical payments.
This has happened to me... twice.
I found out by accident that the motherless freak bloodsuckers who collect taxes in CA entered a tax lien
against me for property I sold years ago. Since I was
a WA resident at the time and could prove it I owed CA squat and was able to get the lien quashed.
Now I religiously check my credit a couple times a year through Chase to make sure they
1. don’t have bogus info and
2. dispute negative info with creditors.