There are one set of twins that were born 87 days apart. One baby  was born on June 1, 2012. The next baby was born on August 26,  2012.
Not until you reach retirement age. Typically that's 65, though many pension plans allow you to start collecting early retirement benefits as early as age 55. If you decide to start receiving benefits before you reach full retirement age, the size of your monthly payout will be less than it would have been if you'd waited. Ask the folks who run your plan to create a simple table showing you how your payments will vary depending on when you start.
Remember that the earliest you can start Social Security retirement benefits is age 62. You can also start it at any time up to age 70. At 62, your payments will be reduced. If you start at full retirement age, now 66 for many people, you'll get your full payment, based on your highest 35 years of earnings. At 70, you'll get your full payment plus a 32 percent bonus for waiting. See also: AARP Social Security Calculator.