Can you sculpt when you use mirror modifier for an object?

Probably I will get comments like: “why don’t you figure it out?” Or whatever.
Well if you aren’t that kind of person, then could you be so kind to tell me if it is possible?

Does it still work when you want to change a small part? I tried to change the radius and strength but it changes a larg area…

I want some thing like this:

But when I use the brush “draw” or other brushes,
I don’t get the same results.
It looks like this when I use a brush in almost the same place:

It changes a larger area then I want to…

What am I doing wrong? How can I solve my problem?

Thank you for your time.
I just want to learn sculpting. I follow YouTube tutorials.

N-Side Panel → Tool → Symmetry …

I tried it but it still gives me the same result. Even if I change the radius and strength of the brush

Have you applied your rotation and scale before sculpting? Also, as said above, you want to use the symmetry tools when sculpting, as opposed to the Mirror Modifier.

Yes I did. Oh that is why.