Who is your biggest critic? Is it your neighbor, your colleague, your spouse? Many of us become our own worst enemy when it comes to getting things done.
Overthinking can prevent you from even starting. What if it goes wrong? What if I fail? What if no one understands? Well you won't ever find out unless you give it a shot. You miss 100% of the shots you don't take. Get out of your head and start trying! Do your research, put in the time and effort and be persistent. You have to do good work, and most importantly, have faith and confidence in yourself. If you're not willing to fight for yourself, who will?
You can do this! You lose if you don't try so stop thinking, start doing. Have a plan and stick to it.
You hold the key.