Can I learn martial arts at the age of 25? Will my body be flexible?

I am 32 right now. I started learning mma and boxing at the age of 31 after nearly a decade of inactivity. I definitely was not flexible enough to do a lot of kicks. I have a 38 year old who trains with me

What are the 'must know' things before turning 25?

Am older than 25 and I guess am best fit to answer this question. These are my 25 things I have known during my journey of life so far. 1. World is not contained in book2. Experience teaches you more than anything/anyone in life.3. Make at-least one friend for life.