With the annuity formula from the principal, annual interest rate and term. The payment is equal every month, but the interest/principal split shifts over time.

With an annuity, interest accrues on the remaining principal, which is largest at the start — so early payments are mostly interest and later ones mostly principal.

No. The result is an educational illustration based on assumptions you set — not a forecast, and not investment advice or a recommendation. You make the decision.