Dear Mr. Dad: My 24-year old son and his wife are expecting their first baby in a few weeks. I’m really happy for him and I’m looking forward to meeting my new granddaughter. The problem is that I’m not even 50 yet and I can’t wrap my head around the fact that I’m going to be a grandfather. I take good care of myself, look pretty good for my age, and just don’t feel like a grandparent. What can I do?

A: This is definitely not your grandparents’ grandparenthood, with its images of grey hair, round-the-world cruises, and senior citizen discounts. Unfortunately, no matter how young you feel, how much you work out, how great you look, or how much of your hair you have left, there’s still one thing that will make you—and everyone around you—painfully aware that you’re getting older: that adorable tot running up to meet you at the front door screaming, “Hi, Grandpa!”

Becoming a grandparent at a young age can be a real shock to the ego—something a lot of us would prefer to keep safely in the future. But, if it makes you feel any better, you’re far from alone. According to AARP (which used to be called the American Association of Retired Persons—and which you can’t join until you’re 50 anyway), the average age of first-time grandparents is about 47, which almost no one considers “old.” A recent study of GenXers (those born between 1964 and 1980) by MetLife found that only 27 percent would consider themselves “old” before age 60. 35 percent said “old” is 60-69, and 25 percent said they wouldn’t be “old” ‘til after age 70.

No matter how much you prepare yourself, once that first grandchild shows up, your life will change in some pretty serious ways. Here are some steps you can take to make the transition a little less jarring:

  • Say “No.” A lot. Will your children be counting on you to help with their baby? If so, that could mean making significant changes in your schedule. But since 75% of GenXers are working (65% full time, 10% part time), that may not be easy.
  • Be a grown-up. Too many young grandfathers feel the need to prove they aren’t old by working longer hours, running faster, and shooting more baskets than their sons and sons-in-law. Young grandmothers can fall into the same trap, but for them it’s more about trying to look younger than their daughter or daughter-in-law. And since they typically have more disposable income to spend on stylish clothes and plastic surgery, those daughters and daughters-in-law can end up feeling jealous and resentful.
  • No turf wars. When you were a kid, grandparents were revered and respected as the senior members of the family. But since you’re so young, there’s a good chance that your own parents—and maybe even your grandparents—are still around. And since they’re older and (supposedly) wiser than you, they may feel that they should have a bigger voice in how their great- or great-great grandchildren should be raised. Ultimately, it’s up to your son and his wife to decide whose sage advice to follow and whose to ignore.
  • Welcome change. No, you’re not “old.” But you are getting older. So by all means, keep living your life. But don’t pass up any opportunities to spend time with your grandchildren. As you no doubt discovered with your own kids, they’re only young once and it goes by in a flash. You’ll never forgive yourself if you miss too much of it.