You are not trying to be someone you are not. The confidence is in the fact that those around you accept you for your strengths and your weaknesses. No one is being pretentious. You have their unconditional love.
When you accept Jesus Christ as your Lord and Savior you are always surrounded by Him as that type of friend. You can put your full Trust in Him. He knows everything about you. There is nothing to hide. God knows all of your faults and loves you unconditionally. He also knows your strengths and some that you are not even aware that you have. He will guide you through life. You will not be led down the wrong path.
As He leads you to new areas of your life, trust that His will is best. He will never let you down. You will take on tasks that let your talents bring Him glory. Sometimes this means stepping out of your comfort zone. Some call this a leap of faith. As you leap forward, God will be your safety net.
Trust in the LORD with all your heart and lean not on your own understanding; in all ways acknowledge him, and he will make your paths straight.
Take comfort in being able to lean on Him. He is available to talk to 24 hours a day. Take the time to pray and express your love, questions and fears about what the future holds for you. He will guide you to your greatest potential. All you need is trust.