It's never too early in your career and life to start planning and saving for retirement.
When should I start planning for my retirement?
From the time you first start getting money. 10% of any money you get as a gift should go into savings. When you get a few hundred dollars, start investing in CDs through your bank, because they have a higher interest rate than a savings account.
Speaking from experience I would say the day you start your first full time job! You live on what you make, if I had a do over I would live on my base pay and put every yearly raise (when I got one) into my retirement. In my profession people generally only live five years after retirement according to statics compiled by our government. As of today I've been retired 5 years, 5 months, and 7 days! But I still have retirement!
From the month of your working, as when you work then you have the payment, so save it a little every month in the bank, further more, it's a long time saving, so you should be persevering and patient.