Can a person become a good trader in half a year?

Not a chance in hell.

Assuming you learn everything in an efficient best practice manner, it is going to take you between 1 and two years of full time diligent work (approx 80 hour weeks) to become competent, and another few years to become good.

Of course there is a shortcut if you have a very good mentor and you are trading his/her proven systems (which only works in rare cases), but it would still not get down to 6 months.

Also, many traders become either patterned on their first win or traumatise themselves taking unnecessary losses. For example I know traders that made good money in 2008 and they are still patiently waiting for the market to crash, they identify as bears down to a core identity level (which is stupid). Or traders who are so traumatised by previous losses that they are chronically risk averse.

One of the problems with trading is the Dunning–Kruger effect which is basically that as soon as you know a tiny bit about markets you will think you are an expert.

How much experience do you need to make 10k a month with trading?

You need at a very minimum several years of full time experience (more if part time) with a deep understanding of markets.

I would say a smart motivated person without making terrible mistakes could do it in 3 years, but it would be 3 hard working years.

To generate 10K a month on average I would estimate you need between 500K and 1.5m in assets.