Confused about things like age

i am wondering which one you should use when writing how old you are cause:

there is 年齢 as years old

and

there is 〜才 as years old

how do you know when to use which?

When you’re talking about how old you are, you’d say ~才 or ~歳 (both are pronounced さい)

年齢 is more like “age”

thx,

so you never use 〜才 in writing then?

才 is taught to children, 歳 is taught later on. Since 才 is easier to write, you’ll see it in handwritten notes and stuff, but when typing, 歳 is more common.

歳 or 才 is used as a suffix when giving someone’s age, e.g. 41歳
年齢 is a noun that means age in the sense of “years old”.

thx, makes at lot more sense now