We've all been there and most of use have a draw or closet full of items we've made mistakes on. You are lucky to have a forum like this. Most of us got into the hobby well before this wealth of information and people to help was available.
So if you are dedicated to this hobby, read through the treads and pay attention to what is said. In no time you will have enough knowledge to be able to stand on your own two feet. And always post here before you buy. No item is that rare that requires you to 'buy it now'.
My greatest fear is that one day I will die and my wife will sell my guns for what I told her I paid for them
"Don't tell me these are investments if you never intend to sell anything" (Quote: Wife)