My three-year-old niece recently got a baby sister earlier this month, and she’s adjusting to no longer being the sole focal point of her parents’ lives.

That’s not really a problem — she’s an independent little girl and has more than enough toys and a cousin to play with.

But she’s also proud to tell people, “I’m the big sister” — it even says so in the t-shirt her father bought her. So she pets and kisses the baby, and then leaves to attend to her imagination when the baby cries.

What her parents and the rest of the family — the grandparents, uncles, aunts and others — are doing, is encouraging her to understand and embrace the importance of the role of being a big sister. A supportive figure; or, maybe a role model. A mentor.

I tried “instructing” my younger brothers when we were young, but they didn’t seem to want any part of it. (I tried telling them “You’re not the boss of me” is cliché, and as long as mom and dad weren’t in the room, I certainly was.)

Parents and siblings are often the first people who leave an indelible impression on us when we are young. As we grow, it’s a simple fact of development that we all need encouragement, direction and understanding. Sometimes it comes from a teacher, coach, family friend or neighbor.

While good mentors lead by example, the best employ — and even encourage — dissent. Or, more euphemistically, a variety of viewpoints. Being a sounding board and playing devil’s advocate can enlighten us on perspectives we may not have considered; at the very least it provides those who instruct us some amusement.

But a mentor or instructional figure (also know as people we complain to) also encourages us to go beyond what they offer and evolve, hopefully, into something more.

My sounding board is on sabbatical right now, but we all hope he gets back from dipping his toes in the soothing sandy waters of time off as soon as possible. I might feel an urge to gripe.

• If you want to tell people the truth, make them laugh, otherwise they’ll kill you. — Oscar Wilde

• Illusion is the first of all pleasures. — Oscar Wilde

• The greatest way to live with honor in this world is to be what we pretend to be. —Socrates

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