It sounds like your question was misinterpreted. You said the policy matured. Generally the amount of money received from the surrender of a life insurance policy is taxable to the amount it exceeds the amount of premiums paid. Refer to Situation 1 in Rev. Rul. 2009-13.
If you received the proceeds directly then you would have to calculate whether the amount received exceeded the cost of premiums. If your mother received the proceeds and gave them to you it is a gift.
