No, that's not bad at all. I added to my order too. I am also in her wool co-op so I'm going to be getting some of the same wool that she uses for her diapers. She's sending my order out tomorrow, I'm SOOO excited.
Is this a custom order you're adding to? How is she policy-wise for doing that? All I know is, if it were me, I would have a hard time knowing what to do - many custom-sewers have a certain number of slots that they can handle in a reasonable amount of time, and if someone were to keep adding to their order (especially after I had started working on it already), it would kind of irk me. I'd be happy for the business, flattered that someone would want my diapers that much.....but still, tearing my hair out because I have too much to do & not enough time to do it.
Anyway, I guess your bottom line would be - ask her. She may be thrilled, or she may be swamped, and only she can tell you!