The word your mortgage lender used was almost certainly "middle" score, rather than average score. That's important in many cases because a person can have a very bad score on one bureau, but the other two scores are good. For example a 761, 760, 630. The middle score is 760 and the average is 717. If the average was used he'd end up paying a higher interest rate in that example. But mortgage lenders use the middle score.
Since you will not be buying a house for many years (if ever) you can forget about your mortgage scores. The scores you should be tracking for the future are your FICO 8 scores, and possibly FICO 9 scores (though most lenders are not using FICO 9 yet so FICO 8 scores are fine).
Be sure that they are not Vantage scores or other non-FICO scores.
It sounds like you may not know what your three FICO 8 scores are. These could be quite a bit different from the middle mortgage score, so I encourage you to sign up for the $1 trial at Credit Check Total and grab your three FICO 8 scores there. You can always cancel the next day.