I would not recommend that anyone start with a .45 simply because of the recoil. That often results in flinching and for a beginner that could become a bad habit that's hard to break.
I agree with what others have said bout a.22 It has very little recoil, therefore you're less likely to flinch and that will enable to focus on trigger control which is fundamental to good shooting.
Having said that , both of my kids (male and female in their 20s) started with a 9mm Glock and it worked out fine for them. I still don't have a .22 but after the hysteria calms down I'll be in the market for a Keltec PMR.
"Socialized Medicine is the Keystone to the Arch of the Socialist State.” -Vladimir Lenin
"I predict future happiness for Americans if they can prevent the government from wasting the labors of the people under the pretense of taking care of them." - Thomas Jefferson (An early warning to Obama care)