At 32, I have outed myself to both my parents. Dad has been cool, we don't really bring up the subject, but he's trying to be supportive in his own quiet way. My mom, on the other hand, is overtly supportive, but has tried to keep the daughter with suggestions such as "maybe you just need more female hormones to feel like a girl?" Then again, Mater tends to still thnk of me as a child, since she said I was misbehaving when I got a tattoo earlier this year.
I didn't need to out myself prior to T (I'm still pre-T), but I chose to because it was my path, your path may be to get T first because of distance or whatever other reason, Best of luck.
Lorenz