People about Cosplay...
To answer your main questions, No and No. Cosplay is supposed to be about inclusiveness, fun, and showing your love for a character.
That being said, as with any group of people, there will be jerks on both sides. There will be those that make their costumes and look down on those that buy them, and vice versa. Jerks can be found at all levels of cosplay, just like regular society. And just like regular society, you have the choice to ignore the jerks and go your own way.
If you are happy with your cosplay, not competing in a 100% bought cosplay and are having fun, that really is all that matters.
People who make their cosplays receive just as many nasty comments and critiques as those that buy them by the way.
There’s a few things – one is that you you’re going to get asked for pictures, especially if you cosplay a popular character.
For conventions, make sure that you have a way of carrying essentials on you, even if your costume doesn’t have pockets. Perhaps make a simple bag to match your costume (same color as your outfit, or decorated with a suitable design, an example being a Jedi costume with the Jedi order symbol).
Wear your costume around before the convention, to make sure that you can move around in it, or that things don’t start slipping/pinching/falling apart after a little while. At home, there’s lots of time to make adjustments and fixes.
Don’t worry if you’re not as good as some of the veteran or professional cosplayers out there. Those cosplayers started somewhere too, and with practice, you too will eventually get good.
To me, it’s equally a tribute to the property that I’m making the cosplay from, and the art form.
One could say the same thing of not getting the appeal of creating any media – learning any instrument, painting a picture, writing a book. It’s creation and display – this may not be the same to everyone, but it’s definitely a big part to me. It’s also a way to meet new friends from all walks of life. I’m certain if you looked closer, a lot don’t meet the stereotypes of an overgrown kid. I cosplay with people in the military, aerospace, tech, and all walks of life. Conversely there’s people that do this for a living, myself included.
As someone that enjoys hobbies and media that was formerly shunned for being “too nerdy”, perhaps immediately throwing anyone that takes part in cosplay into the “you’re a man/woman child” box is a bit reductionist, and a little offensive.