Hi,
Firstly, nobody panic! I'm not going to attempt this at home! 
I am 35 with long dark brown hair and more than a few greys. Not loads, but a fair few. I have a growing out balayage already, but kept my colour quite far down, but now I'm thinking that the darkness of my natural colour against my pale skin, is no longer flattering.
I'm nervous about the commitment tbh, but given I'm going grey and don't intend to embrace that, I will be dying my hair regardless I suspect.
I'm also nervous about damage. I had treatments during my colour to protect it, but it is definitely a little brittle and there has been some breakage.
Anyway, does anyone have any ideas and/or experiences they'd like to share?
Thanks 