Our kids are 2 years apart but in back-to-back grades. Here's why we chose to retain one and not the other.

• Our kids are in back-to-back grades, even though they're two years apart.
• We retained our oldest for an extra year, and our youngest is going to kindergarten early.
• Here's why we made our decision.

When I gave birth to our youngest, now 5, my spouse and I became members of the elite "two under 2" club. Baths meant a baby tub inside the actual tub so they could clean up simultaneously, followed by side-by-side diaper changes and similar bedtimes.

Now, I love that my kids have an age difference of 23 months. They like the same things, play similar games, and almost as soon as one grows out of something, the next is ready to wear it. But something that will bring them even closer together is that though they're almost two years apart, they're in back-to-back grades. Our oldest, 7, will enter first grade this August, while the youngest, 5, will start kindergarten.

We thought a lot about what we wanted to do

The decision of whether to send them off to school is a nuanced one and one we didn't come to lightly. An easy answer is that they both have summer birthdays , which are a bit of a mixed bag on whether parents choose to send their kids or not based on the cut-off date.

My older son's birthday is in June, and my younger son's is in May; my oldest would be one of the younger kids in his class if we'd sent him to kindergarten when he was 5. My younger son's birthday is a month earlier in the year, but he's also just more ready, when, at the same age, my oldest was not.

Another factor is that my spouse was a year behind his own brother in school and loved it; he wanted his sons to have the same privilege. (I was five years older than my nearest sibling, so I, too, understood the draw to be near a loved one at school. It is, after all, why we chose to have our kids close together. The age gap left me feeling distant and on my own for much of my youth, and I didn't want that for my kids.)

The biggest reason, however, is simple: it's what their personalities called for.

Our oldest is fun and lively but has trouble sitting still or listening to directions. It's as if his own brain holds his attention span hostage. He would not have excelled in school as the youngest. In fact, teachers still mistook him for being on the younger end of the class when he did go to kindergarten, even though he was one of the older students . (A revelation that made me realize we had made the right choice for him.) He worked hard and excelled in extracurricular areas, but schoolwork meant tough concentration. Homework was always met with pushback. An extra year of maturity helped him adapt.

Socially, we never worried about him; he's as outgoing as they come. He gets compliments for getting along with others, a personality trait he was blessed to receive. He goes to school to see his friends, not to learn.

Our youngest, however, lives for school. He will happily do worksheets or learning-based activities for fun at home; I got reports that said the same from his preschool teacher. He will fuss at bedtime if he's not done with a puzzle or drawing sheet or whatever he's working on. He likes concentrating and learning. We get constant compliments from teachers about him being well-behaved and a good listener. (These are attributes he does not display at home.) He asks for more lessons, like it's his idea of a good time.

He is more shy and reserved, so I do worry about him starting school at a younger age . He goes to school to learn and makes friends as an aside to being there. To help with this, I enrolled him in a summer learning program where he was able to get comfortable with teachers, learn how to go through the lunch line, and get the lay of the land. This extra time boosted his confidence and made me more comfortable sending him next month.

We hope growing up in back-to-back grades will help them bond

Hopefully, growing up in back-to-back grades will be a bonding experience they can love and enjoy. But more than that, the goal is to have them in the class and developmental age where they can best thrive. If not, we will talk with teachers and reevaluate. There is no right answer, just helping them with the best path to help them succeed.