Wow I haven't been on here in forever!

Okay, so here's the story. This summer between college semesters I had a job at the upscale restaurant where my sister is a server and my brother-in-law is the general manager. One of my sister's friends is a lesbian and so am I. She is a good bit older than me, but I am mature for my age and we appear to be on the same level. At first I didn't expect to feel anything for her, but I found myself liking her more and more. I have never dated anyone before or even flirted for that matter, but I felt like a lot of the things she would say and do around me were flirting. The week before I left to go back to college, she would joke around with me and say things like "I better get a make-out session before you leave." Also, she mentioned coming to visit me at college about 3 times even though it's about 3 hours away. She has met my mother (who also knows I'm a lesbian and is fine with it) and they both get along really well. She even joked with me one time and said "The hardest part is over... you've already brought me home to mom." The last day I worked, she gave me her cell number and told me to call her/text her anytime I needed anything or wanted to talk. About a week into school, I texted her saying "Hey this is K. How are you?" to which she responded "hey you!! Its going long and boring without ya..." so I said (with advice from a lesbian friend) "I bet, which is exactly why you should come and visit me sometime." and she responded "you bet". So I stopped there not really knowing what to say and about a week and a half later later my friend told me to send "Hey, my women's studies professor totally reminds me of you. Its pretty funny." which sounds extremely dorky to me now, but I guess that's what I get for asking my friends advice. So I never got a response and promptly gave up all hope. A few weeks later, I got a chain text from her "I love you lots, like tater tots, and even more than jello shots. You're my friend, til the end... etc.." which let me know she didn't delete my number. Last Saturday, I left college for various reasons, mostly to take a break and figure out what I want to do. So on Tuesday evening, my sister was visiting and out of the blue (not talking about the girl or the restaurant) she says "J was really bummed when I told her that you were home but you won't be working at the restaurant." Neither my sister nor my mom know that I like her because for once I have kept it a secret, but I really want to ask my sisters advice. I'm just afraid my sister won't want me to date her because she's older. So I guess what I need is input from neutral people. Does it seem like she wants to date me or does she seems to just be interested in being my friend? The few friends who I have told have been telling me to call her up already and ask her out to dinner or something, but I can not get the guts to do it. I have no idea what to do!