Women love men who challenge, motivate, and encourage them to do the things they've always wanted to do. But there is definitely a line. Beyond all of this, you need to be respectful of her boundaries (as she should also be with yours). If she says she's not comfortable, she's unsure of something, or gives you a flat-out 'no' make sure you take it seriously, no matter how silly it seems at the time.
She might not want you to push her into the pool, she might not want to try eel at your favorite Japanese restaurant, she might not be ready to quit her job for that creative pursuit yet. Of course, this also extends to the sexual arena. Don't push her, it's really not attractive at all. If you respect her and her boundaries she'll definitely want to hold onto you.