Everybody, no matter what age, is attracted to young sexy people. It's that simple.

She's physicslly young, so I suppose still has the desires of a healthy young woman. I am not sure how i would feel in that situation. Certainly i would consider being with someone mentally much younger than me a disadvantage, but Harrison Ford is also much younge than her

It a little known fact. Dorian Grey dug women whose whole life showed on their faces.

She had a young soul and Ellies had knowledge of the past, plus relationships aren't about age and yes love, they had affinity enough and that lead to love.
"I feel you, pretty baby, feel me
Turn it up hot, lovin' you is free"

107-year-old men are pretty hard to come by.

I think the fact that he was very persistent. He wasn't going to let her go, that broke down her defences. She normally gives men the shaft and they get offended and leave but he was taking no prisoners.

It's okay. 'cause she is a woman. NOT a creepy old man.

Great point! You'd think she'd be surrounded with many old, polished bon vivants who could reminisce and appreciate the good old days. But no, she falls for the pretty ingenues!

what is age?
when we hear about a 50+ women, we get the face of an aging beauty or a face mutilated by plastic surgery, no matter how beautiful she's been just few years ago.
when it's about 100+ years old, I'm afraid we have no other reference but the vampire or witch movies, where her actual face was a scheleton.
so move over these silly images and imagine a 100+ years old girl as beautiful and healthy as she was in her 20s.
that's all about perception

That was my thought on it. He wasn't some immature young guy. He was intelligent, deep, and sophisticated with an appreciation for the finer things. Those attributes are rather ageless.

And don't forget, she fell for a young man with a deep appreciation for the past.

If you look at other stories of immortality, such as Highlander or the vampire in Moonlight (and other stories), the 'immortal' often falls for someone their apparent age, not actual age.

I understand what you are saying.
But consider that the actor she falls in love with is in his 30s, he is not THAT young. And even though she has lived a long time, physically she is a young woman. Maybe mentally too she is a young woman but one with lots of experience and knowledge.
Let's suppose the opposite would have happened, she had fallen for someone in his 100s. In a wheelchair, living in a nursing home. That would have been a pretty strange development, wouldn't it?
But the real reason, IMHO, is the fact that this is a fictional story and the writer knew how he wanted it to end. So everything that comes before the end is setting up that intended ending. So she had to fall for exactly who she fell for!
.... TxMike ....
Take a risk, Take a chance, Make a change.
Kelly Clarkson - Breakaway