There are certain things which doesn’t have any scale to measure it. Yet we make our own scale and tag a person with that.
We live in a world full of mature yet immature people. There’s no ratio in mature vs immature people. Both have the same number as the population of the world. Maturity is one of them, it doesn’t have any scale to measure how mature a person is. It depends on the topic and the opposite person. When there is a topic in which a person has suffered he/she will guide you or on the contrary he/she might show the level of maturity which the other person expect at the moment of time and it could be also because that person might have some benefits, he will say something which the opposite person wants to listen. Based on what we want to listen we tag them with a maturity mark. In reality it is us who wanted to listen it from someone. When the same issue troubles that person he might behave more naive than you have.
Similarly there’s no scale to measure the smartness level of a person. There’s a measurement for IQ but not for smartness. Just because a person has observed or adapted something into his/her daily life, one can do it with much ease whereas one person might get confused at first just because he/she has no idea about that. If one person is smart and the other is not. The latter will find the other person weird just because he has no clue. There are certain example of great scientist where they have invented or discovered great things but failed in doing certain usual activities.
In a summary, we all are equal and no one is master in anything by birth, everyone has made mistakes and learned from it. Just because you reach that level after them you might feel that they are great, but once upon a time they were also a noob or more stupid than you, you never know. One might feel the other person is mature or smart enough than him/her but the very same person might be a noob for someone.
Never underestimate yourself and don’t ever think you are downgraded. It’s just that you have never been through the same situation. What you are capable of, he/she might not be capable in achieving or doing that. There’s certain level of maturity or smartness in all of us we just need embrace it. Never set a bench mark for yourself or for anyone else. Just try to improve yourself and reach where your heart is.