I would suggest that you save the 900 a month for a few months, or more. You will want some for a down payment, and some for reserves.
While you are doing that, self educate, self educate, self educate. I think most here will tell you to buy a rental and I agree, but if you're very risk adverse, early repayment a great thing too. That's why you need to make this decision.
You're in a great spot though! $900 extra a month. That's a chunk of cash. But you're on an investor forum. We think you should invest. Go to a debt free forum, they'll say pay off the home. Go to a corvette forum, they'll say buy a corvette. All will make compelling arguments, you need to decide what's best for you. On second thought, don't even go to the corvette forum...yet
The basic investing argument is that you will be able to do better than the rate on your mortgage, that in 15 to 20 years with inflation, your payment is lower anyway. In 15 to 20 years, your rents will have increased based on inflation. They'll be bumps in the road but at the end of it you'll have solid cash flow. I agree with this
The payoff argument is that it's guaranteed to be paid off, the tenants won't always pay like they should, roofs need replaced, water heaters, tenant turns, etc. I agree with this.
I will say, I've met many older people that worked hard, had paid off homes that were struggling. I have met a few older people that had 10 to 15 rentals. They weren't struggling