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.
If you reach age 62 on September 10, the first month for which you can receive benefits is October because you were not at least age 62 for all of September. Since October is when you are at least age 62 throughout the full month, October is the first month for which benefits can be paid. People who are already past age 62 when starting Social Security retirement can start benefits in the month of their choice because they are already at least age 62 throughout the month. Note: This is a different subject from when Social Security benefits are paid.