Please may anyone help me

Caz
I wish to write a letter to my mother whom ive not spoken to or had any contact with in 20 yrs! I dont honestly know where to start! Ive no idea even what to say. My parents split and it was very violent. My mum left my dad she was so scared she left us and run for her life. We got placed with our nan. I wish to let her know im a adult now not the lary teenager she last saw and i forgive her for leaving us. As a adult i see things in a different perspective and i now fully understand why she couldnt take us and had to leave in order to have her life. I miss her terribly i was a real mummies girl. If she doesnt reply its fine but i need her to know i forgive her im not out for hassle i just wish to speak upin adult terms and hopefully reunite with her. Lifes too short to hold grudges i cant carry on with this burden on my chest each day. Where the hell do i start in a letter? Do i tell her about me and my family? Do i keep it limeted info? Please help id really really very much appreciate anyone that can help me to start a letter. Thanks for reading my post and any further replies.