Most professional authors, agents, etc. will advise you to cut your first draft by about 10%, so you can whittle out the fat and make it clean, lean and entertaining. That advice never worked for me as I always wrote my first drafts far too short. My first draft of my (eventually) published book was so short they told me to add 20,000 words to bring it to standard length.
My background in writing started in media, print and television and eventually the web. Words counts in those areas is ridiculously short but the trick there is to be punchy, get to the point and tell the story as thoroughly as you can in the space allowed. That’s what I did.
That training is ingrained in my writing. I get to the point then have to go back and fill in the details I left out.
I am an innie.
Other people I know write first drafts that can be double the appropriate word count for a specific type of book. 500,000 words makes a really good epic fantasy or a trilogy but a novel of that size is likely to be returned, unopened, postage collect.
This is something you need to recognize in yourself. Just say it: I’m an outie. I write long first drafts so I know that I will be cutting and tightening, using better words to say what takes a sentence or two, when I edit the thing. Don’t worry about it initially, just do it long.
For me, and my ilk, we know we need to look for places to expand, to fill in the descriptions of people and places and actions for our readers. So don’t worry if your first draft ends up at 50,000 words. You’ll put them in later. Just be an innie.