I agree with Dawn. You are expecting way too much. Often they can do things for a while before they can REALLY do things. She is only 3.5 years old. There is no reason to rush. Teaching her sooner (especially if she's not interested, even if she is capable) will not help her in the long run. I'd just back off and let her go at her own pace. If you feel worried about it, there's studies you can find online that show how kids aren't delayed by even completely skipping preschool. Many are helped by it actually! Surprising, eh?
I tried workbooks with my 3 yr old son. They were just fun, simple little things. He was interested in certain pages but not in others. I would try to encourage him, but he just didn't want to. He was not at all interested in writing. When he would try (he usually wasn't interested), it was so funny because he just wasn't there yet. So, we would work on whatever pages he wanted and skipped the ones he didn't want. He also wasn't interested in circling things normal...and often he'd end up with a big doodle all over the page. Honestly, I didn't really care. He was only three. And, to him, he was circling the item he wanted to circle...just a doodle accompanied it:-) I wanted to keep it fun.
When he turned four a few months back, I decided to try to teach him his letter sounds. We were going to do one letter a day. He knew his alphabet, and that was it. So, we started with a letter a day and did fun coloring pages, etc. We kept it simple...though I only made it to letter A before I heard about Leap Frog Letter Factory dvd. So I got that and let him watch it. It teaches letter sounds. Two days after he watched it, i asked him what sound "a" makes, he told me. Then I went through each of the letters, and he knew all of their sounds. I was really surprised. I hadn't taught him any of that. (it's a great dvd!) So, then I thought I'd see how he would do with reading, it was a piece of cake! About four months later, he was at first grade level reading (I use Hooked on Phonics).
Point being, when you wait until THEY are ready (especially at this little age!), you might get nothing for a while, and then suddenly wham, bam they are ready to learn! He still isn't good at writing (he's 4.5 yrs old now), but I don't care. If he's not interested in learning new reading on a certain day, we just read an older book to at least keep up his current reading skills. He's still young enough that I don't push anything on him unless he really wants to do it.
I think your approach is great, btw. You are encouraging and kind, which is awesome. BUT, she's really not interested yet. My son (and older daughter) did that too. They just weren't interested for a while. It is totally normal. I don't push them...and it definitely hasn't harmed them any! My older daughter wasn't interested for quite a while actually. So, each child is different. But when I wait until they are ready, they really take off with it and learn pretty fast.