Welcome to the Forum!
My wonderful better half is one of the top female instructors for the NRA Women On Target clinics in the country, (according to the NRA.) That said we've been teaching ladies shooting for 9 years now and we get to see all kinds and present them with many options.
First,, the firearm must be comfortable in HER hands,, as fit & comfort are big factors. Grips can be swapped for a firearm to fit her in most cases.
Caliber; 357 is much more versitile than 38 spl only. Different ammo choices. Practice with 38 spl light loads for most practice,, but for SD,, load good quality 357 mag ammo. In a stressful SD situtation,, she'll never notice the recoil vs the fear of the threat.
Next,, recoil; A lighter firearm has more felt recoil vs a heavier firearm with the exact same ammo. So, for shooting pleasure,, heavier is better,, while for carrying,, lighter is better. Unfortunately,, there is little you can do about the physics of this. The Ruger LCR is a semi compromise,, but it still has felt recoil moreso than a heavier steel framed firearm.
If at all possible,, have her try shooting MANY different firearms,, with different grips & ammo to find what SHE likes the best. THEN decide what to buy her.