Do you ever expect to be really good at something the first time you do it? I always expect the best out of myself and get frustrated when it takes time to sharpen my skills. I guess this probably goes along with my impatience problem. I want everything right now. My husband reminded me of this the other day. When I first became a mother at 20 years old, I made alot of mistakes. This did not mean that I was a bad mom, just made some bad choices. He pointed out the memory of when our daughter fell into the washing machine because I was trying to hold her with one hand while she was sitting on the dryer while I changed loads. Or when she was in her car seat on the counter and rocked her way onto the floor. You may not have had to learn as much as I did, but we all have to take the time to practice anything we want to do well in.
The same goes for sharing our faith with others. I've felt and heard others tell me that they just can't tell others about Jesus because they don't know enough. You can, it may be difficult, but you can. All you need to begin is your story. How did God touch your heart and when did you accept Him as your Lord and Savior. That is it. As you continue to tell others your story and continue to seek Him through His Word and prayer, it will become easier. Just like everything else in life, practice makes much better.