As long as you are on the right side of the grass, you are never too old

I found the best therapy for me comes via my TG support group. I was totally blown my first ever meeting (age 53), sitting there in a room filled with others whose life stories were practically identical to mine. I thought I knew about everything there was about being trans... Everything except the universe of feelings, and non-feelings, that come along with it. They all were instrumental in helping me turn my life around for the better. A few special angels were also there for me when I really needed them.
If you're near or in a big city that is great. Plenty of options. The closest group to me at the time was some 90 miles away. Add another 90 to get to either DC or Pittsburgh for the closest "Big" cities. All groups have personalities. You may have to try a few out before finding one you feel at home in.
As to how to find them? Google is your friend. A good first pass is an LGBT center, followed by some statewide LGBT advocacy group like "Equality (your state). If you are really lucky there may be a Gender Clinic nearby. NYC, Baltimore, Phili, DC all have one, as well as many other big metro cities. Unfortunatly putting "Transgender" or Transsexual" anything into Google tends to yield tons of hookup sites or porn. A few years back when I was "In Search Of" it took about 3 months of searching a few hours every evening after work in an ever widening then targeted cites/towns/counties near my home until I finally hit paydirt with a support group.
Trans friendly therapist can be found via a local TG support network, or Psychology Today has a Doc-Find with a "Gender-Issues" tick box. But beware, many times that gets ticked because they see LG clients and maybe once had a course where they mentioned trans.
Dressing and makeup is much like the old joke of "How do you get to Carnegie Hall?". Practice, Practice, Practice <rimshot>. Thrift stores are a great way to start. At a few $ per item you get to experiment with clothes. Most department stores have private changing rooms. I used to grab up armloads of women stuff and cover it up with a pair of like size 50 mens slacks and head for the men's changing room. Never had a problem.