The most successful people I know don’t question themselves — but they do question their knowledge. They see asking for advice as a way of testing their ideas, which makes those ideas better and helps them learn.
We also tend not to challenge our mentors too much, blindly following their advice. Don’t get me wrong, this is usually good practice, but we should also make sure we validate things from time to time, especially when they don’t feel right. At times mentors do tend to become a little overly pragmatic and might need a shake up. Take your time to build a showcase for what you think is an improvement so they can easily evaluate it, if it’s good they will embrace it, they should be experienced and smart engineers. If it won’t work, or it’s not an improvement, they will help you understand why, and these are all valuable lessons.