Some people are naturally introverted, sometimes as you get older you gain more confidence in yourself - i know I certainly did.
Often putting yourself in a very unlikely situation can help you overcome shyness, you don't necessarily need an assertiveness class try something out of the ordinary like Salsa Dancing! They are always short of fellas and it's a good way to meet girls, if you go to a beginners class everyone is in the same boat.
I used to teach assertiveness classes and each week their 'homework' would be to do something they wouldn't normally do like take something back to a shop and complain - or tell their boss 'no they couldn't work late'. The idea was they had the full support of the rest of the group - we were right behind them figuratively speaking - each week they'd report back and be congratulated. It was amazing to see how confident people got just knowing they were people somewhere rooting for them. Standing up for yourself the first time is the hardest and you would be suprised at how it gets a luttle easier each time.
Salisbury, we AB'rs are your support - every time you stand up for yourself or put yourself forward remember we are right there with you cheering you on!!
Homework this week - present your idea to your boss and tell yourself you are just as good as your two colleagues, we at AB think you are so go get em Tiger!!
Don't forget to tell us how you get on.