Q. I am almost 13 years old and I have a 3 1/2-year-old brother. My mother is due again in October. Please send me some advice on how I should handle this. I'm not very crazy about the idea.

I was the center of attention for 9 years and now it's gone.

A. I'll bet you're going to handle this much better than you think you will -- and probably much better than you did 3 1/2 years ago. You're not only older and wiser and have better things to think about, but you have something the baby never will have -- 13 years of your mom's life. You've known her at a time and in a way that no other child ever will.

You have wept together and exulted together, too. You were the one who taught her the magic of a child's first smile; the joy of a single candle on a cake; the heartache of a hurt she couldn't do anything about.

You and your mother have stumbled together through a hundred calamities, to say nothing of teacher conferences (which any mother would prefer to say nothing of) and probably a few phone calls from neighbors who said, "I think you'll want to know what your child did . . ."

You've forgiven your mom for mistakes she seldom makes any more and she's forgiven you for some that your brother -- and certainly the next child -- could never pull. You've taught her many tricks of the parenthood trade, and now her job is more serene, less spontaneous -- and sometimes just a little bit boring -- except for you. You're still giving her on-the-job training, because you're still the pioneer; the fresh adventure.

The firsts and the foolishness have made her invest more energy in you, but they haven't made your mom love you more than she loves your brother -- or than she'll love the baby -- but they have made her love you in a special way. And this is the secret of a family. If parents have a dozen children, they love each of them in a unique way. Love comes in different shapes, not different amounts.

This is a fact: No two children ever have the same mother and father. Even twins have different parents, because each child is an individual and invites individual responses.

When the baby is born you may feel jealous (although probably not as jealous as you did when your brother was born) but this time you'll know what to expect and you'll be even more helpful than you were before. The pleasure of being needed will erase -- or at least ease -- the annoyance you'll feel when the baby cries in the night or makes your mom too busy or tired to talk with you.

It may be hard to imagine now, but the baby will have a hold on you, too. You may get mad, but just when you're ready to growl at the baby, your finger is squeezed as tight as your heart, and you'll find yourself smiling instead. In the first year there will be coos to win you and peekaboos to please you, and then when you're finally ready to stand up for your rights -- you'll hear your name in the middle of the babble. You'll melt again.

You might think that the complications a baby brings, both physical and emotional, would take away from your attention, but that's not so. You'll be much too needed to take second place. You'll be needed as a helper, of course, but also as a person who can understand ideas and solve problems. You'll find you'll still be supervised, but you'll be talked to almost as an equal. This will be worth a great deal to you.

There will be many other benefits.

You're going to find yourself a little more mature and responsible than most people your age, because you'll have new skills. You'll be more tolerant and much more protective than you ever expected -- not just of the baby, but of anything small and defenseless.

The baby also will help you put your priorities in order, and you'll find that being a big sister will often be more important than hanging out with friends.

And you'll be more efficient. A baby requires so much, you will learn how to do things faster and in the most orderly way, and then you'll accomplish much more. These are skills you'll transfer to everything you do.

You'll also learn how to do more for yourself and for the whole household, which is the best way to build your self-esteem. There's nothing a teen-ager needs more.

The baby still may seem like the center of attention, but you'll be so important to this child that you'll know you have a center all your own. This only will make you more loving; more giving.