Who you are today, does not define who you will be in the future. Who you are today, is simply you at this moment in time. It doesn't mean you have to stay this person forever. You can grow both mentally & physically - you can change. You can evolve.
It's not easy, but most things worth while aren't. Change takes work, dedication, & introspection. It means taking good hard looks into yourself, performing honest self evaluations, building upon your strengths, & trouncing your weaknesses. It means taking leaps of faith, trusting your gut, & throwing your heart to the wind.
If you're over weight and you hate it - change! Make a plan, get a coach, eat well, put in the work & be dedicated.
If you hate your job and you've always wanted to own your own business - change! Save your money, develop a plan, invest in yourself/education, quit, get your business going, & don't look back.
If you're partner is terrible and your depressed all the time - change! Leave them, focus on you & what makes you happy, get a hobby, be selfish for a while, & grow!
The trail towards your change (growth/evolution) will be mired with obstacles. Friends may not understand, family may disapprove, & you may need to let go of people.
The hardest part - you will doubt yourself at times.
But, with hard work, consistency, honesty, & conviction - you will grow.
You are not defined by who you are in this current moment. Take action towards your goal, it doesn't have to be perfect. Imperfect action is still action.
The time is never right - but the time is right now.
Take flight - don't just be, be great.