I looked at the 100 Easy Lessons book at the library and I hated it, even though I absolutely think all children should be taught phonics and the spelling rules. (Yes, I really think ALL children should be taught those things.) If she's learning sight words on her own, then that's great and I'd definitely
help her with it, but I would not neglect phonics forever. She might not be ready right now, but I really think at some point everyone
needs to understand that the letter A makes the short a sound, the long a sound and the broad 'ah' sound, etc. Otherwise you can't
read new words.
If you don't know what sounds letters make, then new words might as well be written in some code other than than the alphabet, for all the good seeing them on the paper will do you. If you can sound out a word you've never seen in print, you might recognize it and be able to move on, if you can't, then you're stuck trying to find it in the dictionary or guess based on context, which we all know is not always going to be accurate. I think many people never taught phonics eventually figure the letter sounds out without being taught it, but why leave it up to chance, you know?
So I'm not really clear on what you're trying to do, but it sounds like you're just sounding out a word. But does your daughter know what sounds the letters represent? If she doesn't, then what you're doing won't make any sense. If she does, then based on your description of what's happening, it sounds to me like she doesn't understand that you're putting the letters together to read
the word. Knowing the word 'mat' isn't the same as being able to read the word 'mat' and maybe she's not clear that you're sounding it out based on the relationship between the printed letters and the sounds they make? That's what it sounds like based on your post, but I might be missing something.
Either way, I
think eventually she should
learn phonics, but I don't think helping her with sight words will hinder her in any way and I definitely don't think she has to learn phonics right now
. And she might pick up phonics (which is really just the relationship between printed letters and the sounds they make) all on her own by doing sight words. Some people do.