1. Quit worrying about being single. You fret a lot about whether you'll be single and why everyone else is finding a good man except for you. It's not you, so stop worrying about that, too. You'll meet the right man when it's the right time for you and the right time for him (it takes two, remember). Just keep focusing on growing yourself and becoming the kind of person you want to be when you are married. It'll happen, trust me.
2. Good for you, investing your single years. I'm proud of you, single-and-younger-self! Instead of just acquiring stuff, you're using your single years to invest in the future and in eternity. You're going to grad school, teaching overseas (and you once said you hated Chinese food!), traveling more than most people do after they retire, and then you got that crazy idea about attending seminary in South Carolina. (Note to younger self - that was a particularly excellent idea, for many reasons, including lesson number one above!)
3. Spend more time memorizing the Scriptures. You started doing this and older-self-you still has a bunch of colored index cards with Scripture verses on them that you were memorizing at one time. In fact, I need to pull them out again and start that practice again, because at some point, my younger-self-me stopped. But you need it, so don't let anything get in the way. You are going to encounter some hard life situations down the road (don't worry about what those are right now), and when you do, you will need the wisdom and comfort that will come from hiding God's word in your heart.
4. Build other spiritual habits now also, while you can. Habits like regular times of prayer, Bible reading, thanksgiving, celebration. Remember the book you love, Celebration of Discipline? Read that at least a couple of times a year. And practice those things now, while you have time in your day. Because someday you will have (spoiler alert!!) a husband, and children, and a home to manage, and just having time to shower will seem like a luxury.
5. Learn how to cook. Seriously. You will not believe how must stress this will alleviate later if you learn now how to make more than pancakes and pasta.