The age of 25 is a magical time. It's the second (and last) true milestone of your 20s, and it's usually the point at which complete quarter-life crises are induced. You're old enough to have some of your life together, but young enough to still have an excuse if you don't.
You don't have to have it all figured out in your 20s — and certainly not by 25. But there are a few things that you definitely should at least have some idea about, there's a certain degree of self-exploration and understanding that everybody should have by their mid-20s, if not sooner. After all, your 20s are not the throwaway period that most people chalk them up to be (out of fear, usually).
You should know enough about who you are to be comfortable with changing. You should know whether or not you definitely know how you feel about having kids (that meaning, it's OK to not be sure, but you should at least know you're not sure). You should know the essence of what you want to do. The essence won't change, the ways you use that essence will. (Example: you are a creative being who wants to spread a positive message. That's all you really gotta have down.)
The point is: your 20s are your foundation years, 25 is the point at which you need to have at least some of it solidified. Here, a non-exhaustive list of all the things you should maybe (probably, definitely) know about yourself before you turn 25:
What You Value
This is basically what people construct their lives off of, whether or not they realize it. It's never a matter of determining what you want (everybody wants multiple things at once, often opposing things, hence internal battles, etc.) — it's a matter of determining what you value. What you're going to care about more.
How You Communicate With Yourself Best
Most people don't like to wait until their emotional states are so out of control that they have no choice but to address the issue at hand... but most are left with little or no choice because they don't know how to communicate with themselves. Some people write, others meditate, others hone in on their emotions and learn to interpret them. It doesn't matter what you do, only that you do it.
What Your Predominant "Negative Pattern" Is
If you trace back every unpleasant experience you've had in your life, there's usually one core feeling or idea or pattern that will emerge. The reason why this is really crucial to understand is because you don't want to keep re-enacting it, and if you address the underlying cause, you won't have to anymore. More importantly: when people learn how to turn their "negative patterns" around is usually when they find their greatest strengths. It's by contrast that we see and learn.
Whether Or Not You're Certain About Having Kids
You don't have to know for sure, but you have to know whether or not you know. Are you one of those people who has always been a definite "Yes!" Are you leaving it up in the air? Is it a matter of finding the right partner then seeing how you feel? Any of those are fine, but the point is that you really have to sit with yourself and ask yourself honestly how you feel. It doesn't have to be your answer forever, but it needs to be your answer for now. (It's one of the top three "make or breaks" in relationships.
The Essence Of What You Want To Do
You don't necessarily need to know how you're going to do it, but if you can tap into what the "essence" of what you'd like to do with your life is, you'll have a kind of "knowing" that makes everything else a little bit easier. The ways we do the work we love can change, but knowing whether we want to help, or teach in a general sense, or do something creative, or be an entrepreneur sets the stage in a really crucial way. The fruits of those labors may vary, but the roots will be constant. Figure out what they are.
How You Express And Feel Love
Your love languages, that is: how you speak them and how you hear them. This usually has a lot to do with how your parents loved you, but either way, you should know how it is you love someone, especially romantically. It's the key component of building the relationship you want.
What Traits You Think Would Have Saved Your Parents
We're inclined to try, beyond most other things, to develop the traits that would have saved our parents. The opposite of those traits are the things we fear the most and the things we reject most strongly within ourselves. Figure out what it is that you wish your parents would have or could have done, and see whether or not it's a genuine weakness or just a projection you're carrying with you. You'll have a lot more time and energy on your plate if you don't use it all trying to do what your parents should have.