Quick Question

If you want to have kids… and still be young enough to enjoy your grandkids.

My mind went blank and just found the non benefits.

You have kids at your most fertile and most energetic years.

Leverage your youth, beauty and low (hopefully) body count to negotiate for as best a deal as possible.

Enough time and energy to plan career and family goals.

Enough time to make and correct mistakes before the jadedness of aging seeps in and locks you into your bad habits.

Biology
If your parents waited until 40 to have a kid and you waited until 40 to have a kid - that kid would never know their grandparents. PLUS you have to take care of an aged parent whilst bouncing a baby on your knee = no fun.

If you're in love no need to ask. If you're not none at any age.

Contrary to what most people are saying, there isn't any real benefit other than evading social pressure. Romance, children, having a life partner... none of those really depend on marriage.

Marriage matters more towards the back end. It's easier to get power of attorney for medical, secure visitation in health care centers, and sort out inheritance stuff if you are married. Those things are also doable without marriage, marriage just greases the wheels a bit.

Children. At 30 a woman might tend to be more erotic and romantic

When it's your dream to marry someone you love and have a family why not start early. Hopefully the start of a long life with someone you love.

if you have kids when your young,they grow up move out,, you hope,,you can have some of your retirement life in peace,,some times,,

If you want to fit the expected social mold, that’s the only supposed benefit.

Possibly giving birth to healthier offsprings. The younger the healthier

Kids.
More time together.
More growing together.
More shared experiences...

I don't see the point.
You're still fresh out of college likely and still starting out in your career. In your 30s you're likely settled financially.

Building a stronger bond earlier on with your so. For a stronger, more durable family core.

You still have a chance at finding virgins