Next time you see her, just say "hey, I've seen you around. I don't know that many people here and am always looking to make new friends. Interest in getting coffee sometime?" and just play it straight. Then later on when you're friends if you offer your arm to help her navigate it won't feel like pity.

Couple things to keep in mind, as a blind person who's been on the other end of far too many of these conversations.

1. You asked once, and that's fine. Generally speaking, if we need help, we'll say so. You didn't assume, which automatically makes you smarter than the average bear.
2. Don't take it as offence, or get offended, if your offer of help is refused. IT's very possible he/she hasn't done that route before/often, or it's changed in some way that he/she needs to get used to. We don't generally refuse help out of spite (well, we try not to, anyway). However, often times doing it ourselves is how we figure out that oh yeah, we meant to turn left way back there. If you help, he/she might not figure out where they might have taken a wrong turn, and the next time they're in the area they're going to need to figure it out again, and you're likely not going to be there. Also it depends on your definition of "help". IF I ask you where this room is and you tell me I passed it 3 doors ago, you've helped.
3. What would you do if you still wanted to get to know this person and they weren't blind? Ask yourself that question, and then do that. It could be as simple as "Hey, your class is on the way to mine, mind if I walk with you?", or as u/Finishedschool said, an invitation out for coffee. If you want a friendship with this person, then be friends with this person. He/she may ask you to help with this or that thing on occasion. Or, you may find you need their help with something. That's normal.
4. Please, please, please freaking please don't use a sentence containing the word "inspiration" where this person is the subject. If this person is anything like me, you're the 75 millionth person to say so and it gets really old really quickly. You may not mean anything by it, but I've been called an inspiration for walking out of a Starbucks with coffee in hand. I've been stopped on the sidewalk by people who just wanted to say they have mad respect for the fact I can do what I do every day. And that's wonderful and all that. But if your mad respect for my ability to do the exact same things you do without thinking about it causes me to miss my bus, I'm going to be mildly annoyed. I'm not going to say so, because I'm only an asshole to people who deserve it and you not knowing better doesn't qualify, but still, mildly annoyed. Possibly slightly more than mildly if my having missed that bus requires I make "sorry I'm running late" phone calls.

Beyond all that though, try to remember he/she is pretty much exactly like you, and approach them from that perspective. You, and they, will feel much less awkward about it. And you'll probably avoid putting your foot in your mouth more than you think.

Most people with disabilities like to be independent, and every person with a disability hates being pitied. If you want to be friends talk to them like you would anyone else.