People about Cosplay...
I would recommend starting out with something simple.
At my very first anime convention, I only had about a month to prepare and didn’t watch a lot of anime. I did Android 18 from Dragon Ball Z as I had most of her outfit already and had the right hairstyle for it. I only had to do a bit of alteration and get some extra items from eBay.
Each time I have cosplayed since then, I have expanded my range. I discovered I have a knack for props and makeup but am not very good at sewing. Therefore most of my best cosplays have involved some sort of prop or latex bloodwork. I am still practicing my sewing so I can incorporate that as well.
Play to your strengths and you’ll soon discover which areas you prefer to work in.
The only place it should really matter is in competition. Don’t enter a workmanship based contest with something that you bought or commissioned, and don’t take credit for the work of others.
That said, some contests have a category for commissioned or purchased costumes, you would be fine if you entered there.
Cosplay is used to portray a character, in complete characterization, sometimes even down to speech and acting.
Culture appropriation, in my opinion, is always negative, portraying double standards that favor white people. For example, hairstyles used by black people seem trashy and inappropriate, but in white people they are deemed edgy.
Cosplay is a representation of the love for a character, they are acting as the character, their race or cultural background of said character usually has nothing to do with the character, it is a simple fact about them.
When a person does “cosplay”, by making fun of another race, say they dress up as a black character by simply putting on brown makeup, this is racism.
However, correctly portraying the character who happens to be black, is cosplay and is not appropriating the culture of said character, simply using their image to act as them.