Should I ask her out?

This is a classic question, of course, but the answer is unclear to me. I've been hung up on this woman for a while now and I want to decide whether I should risk asking her out or whether I should just move on. I've decided that I want to date during my reboot, so my choices seem to be to either ask her out (in which case I'm possibly risking our friendship) or date other people without asking her out (which she'll probably interpret as me not being interested in her). Here's why I want to ask her out:

• Primarily, I really enjoy spending time with her. We go to the gym together on a regular basis and those times are usually the highlights of my week. I find her really easy to talk to and joke around with. I don't even feel awkward/uncomfortable/under pressure around her, which is incredible.
• She's really attractive. Enough said.
• She and I complement each other nicely. She's social where I'm reserved. She's confident when I'm skeptical. She acts when I think.
• We have a lot of similar interests/hobbies. We like similar music and books and we share a couple of hobbies and workout preferences.
  
• If I'm being completely honest, part of my motivation for wanting to ask her out is that it will be easy. I don't know many single women, so the fact that she is available means that I can avoid some discomfort in finding a (relative) stranger to ask out.

Here are my concerns about asking her out:

• I think she has a better option than me. There's another guy who she spends a lot of time with and who she'll (at least occasionally) prioritize spending time with over me. They do cool adventure-type things, whereas she and I mostly do less cool indoor workout-type things.
• I asked her out once last summer. She turned me down, saying that she was getting over a breakup at the time (which is true, since I confirmed this with a mutual friend). We stayed close friends after that, but I'm worried that asking her out again will damage our friendship. She's one of the few close friends that I have in this part of the country.
• I'm pessimistic about the likelihood of success. I'm concerned that my pessimism will negatively affect the outcome and maybe it would be best to wait until I can be optimistic about my chances.

Thoughts? Thanks for reading!

 

Thanks for the responses, guys! These are good thoughts and at some point soonish, I'll make a decision.

Yep, this is important to me, which is part of my concern.

I don't think I'm at this point, but I might be getting there.

Kind of? Lots of eye contact, occasional physical contact, and we frequently poke fun at the other.

This is a good point! Her going on a date would definitely not kill my interest in her.