Girl at the gym seems interested. How should I initiate?

There is this girl(17/18ish-f) at my(19-m) gym that is making regular eye contact with me.

Problem is, I've never walked up to a girl and introduced my self. Im not an socially awkward person but I do have some kind of mild social anxiety. (Going to social events always feels like a HUGE drag until I get there and I end up enjoying myself a lot).

I think this is a very good opportunity to walk up to a girl who I am interested in. She always works out without headphones. I caught her looking my way multiple times. My gym buddies told me "she has a nice ass but an ugly face", imo she is hot. She has a pretty fit and well build body. I am somewhat the same, not so attractive face but attractive body, this is a good thing because it will give me more confidence on the situation. (I can imagine talking to super-super-hot girls will make me less confident because of all the guys that have been hitting on her in the past that are all way better than me) She always works out late because there are less people. But she also goes when its busy, like on monday.

I really wanna go up and talk to her and I feel like if I won't do it this time I am really gonna beat my self up for it in the future because of all the things I listed above. There are literally no excuses this time.

Now my question is, what would be the best way to do it? I feel pretty unconfident walking straight up to her after she's done with her set and introduce my self out of nowhere eventhough the gym is a place where I feel very confident in general.

What I thought of was just doing ab exercises next to her (we only have 2 ab benches right next to each other) and then after we're finished with our sets start a conversation with her about the particulair exercises she's been doing or anything related to working out in general while getting to know her.

I also believe that she's pretty new because I've seen her performing multiple exercises the wrong way. (Her triceps pushdowns look like a lat pull overs and stuff like that) and this may be an opportunity for me to teach her some better form and proceed to introduce my self.

I think the second option would be better, any opinions? Ever since I had the idea in my mind to go up and speak to her I have been getting butterflies in my stomach because this will be the first time I'll walk up and introduce my self to a potentional girlfriend, dont get me wrong, I have had girlfriends in the past but they were all friends from friends. I am just very new at this picking girls up thing. I believe I really should work on this or else I'll end up being single a lot longer than I would like.

Tl:dr - made eye contact with a girl in the gym, what would be the best way to approach her?