@G Referee SCO I have some good news, and some bad.
First the bad news. You got that call wrong. Shouldn’t have carded for that.
Now the good news: regardless of what others may say, you will probably go on to be a good ref. Why? Because you’ve doubted yourself, and you’ve taken steps to rectify that.
The “learning environment” is difficult for a new (and not so new refs) ploughing our trade at the lowest levels: we’re on our own. Typically, 11 players and 1 manager will agree with your decisions, whilst 11 players and 1 manager will disagree. You get no unbiased sense of if you are doing a good job or not. For me, as time went on and teams were happy(or, at least, not unhappy) to see me rock up to officiate their games, I realised that I must be doing something right.
You have to become reflective, self aware and analytical. Using this site can be a great resource to ask questions if you are unsure of actions you have taken on the pitch, do come and share them here. On the whole, the forum is forgiving if you come seeking advice having (possibly) got something wrong.