I am an old person, i am retired, i just want to keep my mind active, that is why i am trying to learn, html to open a web page, is this place all right for me, or only for young people.
It’s good for all ages, with the proviso we need to be motivated and determined self-learners. If you start with HTML and keep the W3C documentation close at hand as you learn new tags and attributes the take away will be confidence and readiness to go to the next level, CSS.
Neither of these are programming languages. They are purely declarative with the author in complete control. It takes time and practice to learn, so take the time and don’t set the bar too high for yourself. Keep it simple.
Computing and Programming are undoubtedly excellent tools to keep the mind sharp.
If anything I’d say you don’t have the pressure of success to worry about. You are in a position to truly be a hobbyist.