I'm just starting a PhD too! In a somewhat related field, too, . I'll be studying second language acquisition, and I plan to focus on language assessment. I share your excitement. I wouldn't say I feel nervous, though... the negative feeling I have would be insecurity, I guess. Insecurity even though I'm really happy with how my applications turned out and the program I ended up choosing. I've started meeting more people in the program, and seeing how smart everyone is and the cool work they're doing feeds the excitement and the insecurity, haha. But I've had this problem for the past year or so where I compare myself (not yet started a PhD) to friends/colleagues in their 2nd+ year in a program. Even though I tell myself that's just silly to do, it's hard to shake. From what I've read, though, academic insecurity may never go away: (the article focuses more on women, but men are susceptible as well)