How can I ask my cousin if I will be invited to her wedding?

My first cousin is getting married in May. We lived close to each other growing up, but we now live in different states. She lives in Pennsylvania, near the rest of our family, and I have lived in North Carolina for the past four years.

We are a typical amount of “close” for first cousins. We were never best friends, hanging out outside of family functions all of the time, but we have always talked at family functions and gotten along well. Currently, we interact on facebook and play games with each other on our phones.

She is having a relatively large wedding, so I assume I will be invited, and I would love to go, but I cannot be certain I will be.

The reason I need to know now is because I have a work trip that will conflict with her wedding, and the work trip is being booked soon. If I will be attending her wedding, I will need to make different arrangements with work to arrive at the conference after it begins.

It is always tacky and uncomfortable to ask someone about an invitation, but I really do need to know now because of the work conflict. Is it acceptable to ask in this case? And if so, is a facebook message appropriate?

Here is a draft:

Hey [Cousin],
Only six months to go now! Wedding planning must be super exciting! You and [your fiancé] are SO cute.
I know it’s early to ask, but I wanted to know if you were planning to invite out-of-state first cousins to your wedding. If you are, [my domestic partner] and I would LOVE to come, but I need to know now because I have a conference for work in Florida the same week. I can definitely make it to both your wedding and the conference, but the conference submissions are due in a few weeks, and I will need to specify the dates I will be at the conference at that time.

I’m not sure how this sounds, so suggestions? Criticisms? I’d like to be as non-awkward as possible. And how about the mention of my domestic partner? To be honest, I would only even attend the wedding if he could come too; I really wouldn’t want to fly to Pennsylvania and attend this function alone. Can I assume that if I am invited, he will be also? (My cousin has met him at family functions.)

Thanks in advance for the help!