My accent has changed my whole life. When I was younger, it was very Nigerian, then when we went to England, it was very British. I think I have a very strange, hybrid accent, and I've worked very hard to get a solid American accent, which is what I use most of the time.
Be sure of what you want, focus, work hard, be ready to pick yourself up, do not take rejection personally, be as prepared as you can, always be learning, and eliminate negative people from your life regardless of who they are.
Other people do better going on to grad school and others yet are naturally inclined and do just fine without any formal training at all. Everyone is different. The only things I think are imperative are focus, determination and hard work.