I write all the time, just get your ideas down and don't worry about if it seems nerdy to you or whatever. The key is when an idea hits you just write it all down, you can always go back and edit it later. I'd never get any writing done if I allowed myself to second guess everything I write. A person can be their own worse critic, especially somebody naturally creative like you. Just open your mind, push all your fears aside, and let the words flow. I bet you are a lot better than you think you are!