Becoming a homeowner was, without question, one of the most exciting financial milestones of my life. But I'm no mortgage expert, and there were definitely some things I had to learn along the way.

Here are three things I learned during -- or after -- the home-buying process, all of which I'll be keeping in mind for next time.

1. 15-year vs. 30-year isn't just about how quickly you pay it off

Common knowledge might tell you that a 15-year mortgage, if you can afford it, is ideal. In exchange for higher monthly payments, you'll enjoy a lower interest rate and pay off your mortgage twice as fast.

But a 30-year mortgage may actually be the better financial choice, because it leaves you with more cash to invest every month. Warren Buffett, for example, could've easily bought his home in cash. Instead he took out a 30-year mortgage and invested what was left. If your investments earn more than the additional interest you're paying, then you're coming out ahead.

You don't have to be like Buffett. But the point here is that the flexibility of a 30-year mortgage might mean more to you than the lower interest on a 15-year mortgage.

2. Buy down your rate if you plan to stay a while

One trick I was able to take advantage of: paying more upfront to lower my interest rate in a process called "buying points."

Typically, each "point" costs about 1% of your loan amount and lowers your rate by 0.25%. If you have a loan of $300,000 and a 7% interest rate, for example, you could pay $3,000 to lower your rate to 6.75%.

If you plan to stay in your home long term, buying down your rate can save you thousands in interest. But if you're not sure how long you'll stay, it might not be worth it.

In my dream financial scenario, I'm able to hold on to this starter home and rent it out when I move away -- which means buying down my rate is absolutely the move.

3. Be prepared for all sorts of unexpected costs

Here's the thing I didn't exactly see coming: thousands of dollars in onetime charges.

Your down payment is far from the only thing you'll have to budget for. You've also got closing costs, which include things like lender fees, title insurance, and appraisal. All told, they'll typically cost you 2%-5% of the home's price. For a $300,000 home, that's $6,000 to $15,000.

Then you've got property taxes. And homeowner's insurance. And HOA fees. And then you factor in moving costs, appliances, furniture, renovation, repairs…

In short, be prepared. I'd recommend having tens of thousands of dollars stashed safely in an emergency fund for whatever you need in those first few months of homeownership. You'll be much better off than I was.

Apply for a flexible, manageable mortgage today

Buying a home can seem complicated, but it's also fulfilling. It's easily one of the best financial decisions I've ever made. Just make sure you know what to expect going in and put yourself on the best financial footing from the start.

When it's time to compare offers, check out our list of the best mortgage lenders to get started.