It really doesn't hurt to ask. Take a shot, the most she'll do is say no.
She could laugh in your face. Happened to me. I didn't even ask her on a date, she was going on during the last lab of a comp sci class how she was going to miss me. I suggested we could still hang out. That still stings.
You could blow the delivery because you don't know what you are doing, seriously creep her out and make a mess of things and make things awkward as word got around. Happened to me.
You could talk to a girl at a bus stop and find out through the grape vine that she was seriously creeped out, happened to a friend of mine, or she stopped taking the bus, happened to another friend of mine, that guy isn't all that weird nor fugly.
All sorts of bad shit can happen if you are even slightly awkward or on the unattractive side.
As for your story, assuming you are not Don Drapering, and at least your stories are possible, well I knew a guy who smoked 5 packs a day and lived till he was 104 so that sounds like a plan. For that matter for every guy who made it to Hollyweird or the NHL there are many others pumping gas in Flin Flon or parking cars/sucking dick in Hollyweird because they gave it their all. Kevin Smith makes a big deal about how he maxed out his credit cards and spent his student load financed tuition refund and made it big by making his movie. This is horrible life advice, sure it worked for him, he had something, most people don't and even if they do it, you need the right timing and luck.
She was throwing signs she was into you, and you correctly picked up on it. Not everyone has good hetdar and asking out someone half your age if you get it wrong can blow up in your face. Surely you must appreciate that.
I had something similar happen to me with a 30 year old when I was around 50, Knew her ages ago when she was a teenage and living with and knocked up by some 50 something. Small town so I'd see her every 5 years or so, but she was with that guy or another. I see her at Wal-mart and she broke up with guy 2, without me saying anything she says "If we have sex, I don't want a relationship" She shows up a few days later, initiates everything, then makes up some paranoid delusional story of something I never did and I haven't seen her since. So yeah, even a fugly chud can strike gold once every 50 years but I wouldn't base life advice on that.
Had a girl who I found out 30 years later was into me when I knew her at university. I kinda wished I tried something but she was painfully shy and her English wasn't great either. I did invite her to the campus bar during the day as it was a quiet place to hang compared to the rest of the student center, it was a bit of a push to get her there and I put it as, hey this is a quiet place, not hey I want to get up in them guts. After that I figured she wasn't interested. Met her 30 years and boy I was wrong, but she was married with 2 kids and all about that jebus so too late so sad. I could have pushed harder I suppose but on the basis of what.