I always think that most of the time we create our own insecurity. For example, ff you ever feel like you have impostor syndrome, just ask yourself, what are the odds of you really being here by mistake? Of everyone else being much better than you? They're always low and they're is always going to be someone else in a similar situation to you. As another example, if you apply for a job and get a rejection, where only 5% of applicants pass, there is no reason to bring yourself down, 95% of people will be in your same situation. The odds of passing were low but the only way to beat those odds is trying again, and 5% is much better than 0. Many use realism to be negative but I believe it is the best way to have a positive attitude and keep going!

I know it sounds super cliche but if you can find something you enjoy doing you're almost certainly going to be insentivised to do it more often and do it well. Obviously there will be times in your career where you struggle and find things difficult but if you have a goal you're determined to work towards and you can find enjoyment in your work you will succeed.