Buy term life insurance from an A rated Insurance Company, you can find them on the internet and put the difference in an a mutual fund. Do your research on the internet. You will find funds that are geared to pay college education, this is the type of fund that you are interested in.
Just type term life on the search bar and you can find out what term life will cost you based on your age and amount of insurance, usually less than $100 per month. Then compare it to the whole life cost.
Next look for top rated high yielding mutual funds over the last 15 years. A fund that knows you wouldn’t be withdrawing your funds for the next 20 years invests differently than a fund that worries that the investor will withdraw their money anytime they are not happy with the return.