Take money from social security when you arrive at 15.

When you reach retirement age, you can retire at the insured place and receive a pension. According to the Interim Measures for the Transfer and Continuation of the Basic Old-age Insurance for Urban Enterprise Employees

Article 6 When the insured persons with inter-provincial floating employment meet the conditions for receiving benefits, the place for receiving benefits shall be determined in accordance with the following provisions:

(a) the basic old-age insurance relationship in the domicile, the domicile is responsible for receiving treatment procedures, enjoy the basic old-age insurance benefits.

(2) If the basic old-age insurance relationship is not located in the domicile, but the accumulated payment period in the domicile of the basic old-age insurance relationship has reached 10 years, the local treatment collection procedures shall be handled and the local basic old-age insurance benefits shall be enjoyed.

(3) If the basic old-age insurance relationship is not located at the domicile, and the cumulative payment period in the locality where the basic old-age insurance relationship is located is less than 10 year, the basic old-age insurance relationship will be transferred back to the original insured place, and the payment period will be 10 year, thus enjoying the basic old-age insurance benefits.

(4) If the basic old-age insurance relationship is not located at the domicile, and the accumulated payment period in each insured place is less than 10 year, the basic old-age insurance relationship and corresponding funds shall be collected at the domicile, and the domicile shall go through the formalities for receiving the benefits according to regulations and enjoy the basic old-age insurance benefits.

Further reading: How to buy insurance, which is good, and teach you how to avoid these "pits" of insurance.