Hard to ask for what I'm worth

I just filled out my first freelance invoices, where I had to bill OHSU for the hours I worked on different projects. I have to break out the invoices into marketing and communications, and then by specific project.

I kept track of my hours I worked, but even when I was keeping track of my hours, my natural instinct was to say it took me less time than it did, I think because I thought...they won't think it really took me x hours, even though they weren't expecting me to do everything in an hour. It took me a while when I worked there, so why would they expect that to change?

And then when I had to through for the invoice, and assign hours and dollars for projects, it was hard, I again wanted to sell myself short. "What if they get mad about me charging so much? What if they question it?"

Now, logically I know (and Tim has been reminding me), that I didn't make up my hourly rate on a whim. I was initially going to charge less than what Kathryn's bad freelancer charged (who essentially submitted my notes as her work-- not a finished product). And I got a range from Sue's other freelancer, and I immediately put myself in the very low end of that range.

I don't know why I am uncomfortable to ask for what I am worth, or to charge for the hours I actually worked.

As Tim reminds me, they could possibly get someone a little cheaper, but they wouldn't know the material as well or possibly be as reliable. They also know generally what I'm charging, and Sue especially was surprised I finished one of the projects so quickly, so she certainly wasn't worried about the hours (and she just gave me a ton of new projects, which will require a lot of hours). But it was very weird to bill for my services.

That will have to be something I work on, getting more comfortable charging the hours I work, and getting more comfortable charging what I know is a fair and market rate.