I'm not afraid of heights...it's the widths that scare me.
You want to know if it's OK, well as long as you are comfortable and safe. Once you climb up...getting back down to the ladder is the scary part. Make sure someone is there, to help if you fall.
If you are determined to DIY maybe rent some staging...and get some other things done also.
Just a thought, sometimes it is better to get someone out to do it. This frees you up for other DIY stuff.