I admit it, I’m a child of the '60s, and when I’m attracted to someone the phrase I use is “turned on.” But I’ve just been made aware that “turned on” is as ancient as “23 skidoo.” So what is today’s jargon for being attracted to someone?
(I’d ask the people I know IRL, but it’s kinda embarrassing to admit to being so unhip.)
I’m a child of the 80s so my slang might be outdated as well, but I’ve heard “hard for.”
I think that turned on is still an appropriate term, but more for a state of sexual arousal. In the 60’s it also meant buzzed or enlightened, didn’t it?
Today it might be “hot for.”
“I’d tap that.” or “I’d hit that.”
My MIL refers to feeling drunk as being “high.” As in, “we were so high the other night that I went straight home and fell asleep.” We tell her that this means something entirely different, but she doesn’t listen.
She’s a child of the '60s, too! You’d think she’d know!
To the OP, I rather like “fancy.” As in, “I fancy that cute new guy.”
I’d assume “turned on” meant the person was horny and needed some sex, stat.
She’s not the only one. I’ve heard that use of the word as far back as 1974ish.
“Hey, I think that guy is into you.”
You know when your mouth’s gettin’ dry, you’re pretty high.
“like like”
Or would like to be further into you. 
In the 1960s, it meant tripping on LSD.
Cite:
“Turn on, tune in, drop out.”
If I was attracted to someone I’d say I like them. I might also say I was turned on if I was aroused. I would say someone is hot too, from time to time. Sexy works well too.
I always thought of ‘fancy’ as a britishism. Good to hear it is getting some play over there too.
Turned on, to the extent I’ve heard used by my (under 30) friends, is definitely used in this sense.
E.g., “would you stop bending over in front of me while you’re wearing that dress? It’s turning me on!”
“Tingly”
Yeah, my dad (born in 1946) once used “stoned” to mean drunk. I was confuselated. I mean, he was 21 during the Summer of Love, he should know better!
Joe
In the 60s, “turn on” could mean several things.
taught, showed, explained: He turned me on to how to make these really cool headbands.
aroused: I was really turned on by dancing to the music in my head.
High on drugs: Man, he was really turned on when he smoked that weed.
What would you say if you just liked them without being attracted to them?
Grandpa Simpson had the correct answer for questions like this
“I used to be ‘with it.’ Then they changed what ‘it’ was. Now what I was ‘with,’ was no longer ‘it.’ And what is ‘it’ is just weird and scary to me.”
I think the OP is gay so in that case couldn’t he say, “I’m gay for…” 
(I think that’s also from “The Simpsons”)