Mom just signed up for a whole life insurance policy (through something that was mailed to her) but I am suspicious.

In some of these types of insurance, if you die within the first two years it only pays the return of the premiums paid plus interest, not the face value of the policy.

Look at it this way, she comes out ahead if she dies within 6 years (you pay in advance).

Does she have other insurance or assets to cover her final expenses? She may be trying to make sure she is not a burden to anyone when she dies. It may not be the right policy, but if she wants it and can afford it, okay.

By law, every insurance policy has a 'free look' period. The length of time depends upon the state she lives in. If she really 'just' signed up, she can cancel it. The free look period begins when the policy is delivered. Call the company that issued it and ask for an explanation of the coverage. Frankly, I'm surprised that such a policy is even available to someone of her age.