Yup. Only a .45 will do. Anything else is totally worthless, and no more deadly than a paper cut.
You do not walk away from a .45, and I have that from a good authority...an EMT with years of calls under his belt.
Where did he say all of that? Buying a .45 is an excellent choice. It has power without the magnum recoil. I have a 110 pound Daughter-in-Law who uses factory loads in her carry pistol with no problem.