Consider marrying early

Financial:

(Assuming your partner earns comparably) pooling together incomes and centralizing expenses is extraordinarily advantageous. The purchasing power of a combined income versus two independent incomes allows much bigger investments. Returns are measured in percentages; an increase in absolute investment amount is a straightforward increase in absolute returns. Financially, you'll be better off married than single.

Accomplishment:

I believe people hold themselves to higher standards when around people they care for or trust; I attribute many achievements to being around people who inspire me and whom I want to impress. This naturally extends to a partner: the desire to care for another person can elevate your quality of living and work. I think I'll try harder at a lot of things if I know I'm working not just for me, but another who's counting on me.

Well-adjustedness:

My mom often encouraged me to embrace my friends in college: "I'm worried you'll forget what it's like to hug someone." I suppose her fears were well-founded in hindsight: I was maniacally focused in the early days. Talking to people you trust and love is essential to good mental health. I can only imagine that having a partner would add to my state of mind.

Fuzzy feelings:

Having someone to look forward to when coming home from a long day of work. Having someone to look after you in sickness. Someone who is an extra pair of eyes and covers your back. Reciprocating all these kind acts back to! This is good for the soul.

Avoiding pitfalls:

Being around a person you respect and want respect from helps you avoid monetarily or medically harmful habits. Your friends and your partners are people you've chosen to be around and trust; if they tell you that something's off or a bad idea, you should take their thoughts very seriously and re-evaluate. Their support during trying times can change your life.

Financial:

Investments, famously, compound. Every additional year of income pooling and centralized expenditure leads to additional six figure (or higher) outcomes by retirement time.

Companionship:

I stopped living in my home for the first time to come to the United States at 17 years old. I am now 20. I have lived with roommates throughout my time at university; it's been good. Nevertheless, I am sure that the bonds of marriage will give me more fulfillment than what living with a roommate could. From a hedonism point of view, I should surely aim to maximize the number of years cohabiting a spouse instead of a roommate. (Living alone ranks below this for reasons listed above.)

Children:

If you intend to have children, note that the rate of birth defects and infertility rises between the ages of 30 and 35 in women. It seems better to meet a partner earlier in case you want to have children so you can have them with less risk and less medical complications.

A larger pool of people:

The dating pool nearly monotonically decreases with age as good candidates continue to pair with each other leaving less and less people in the pool. Though it may be the case that many good candidates may intentionally enter the market later than you, you are exposed to them if you're still in the market.