It will be necessary to choose a genre (or a narrow list of genres) when you get ready to submit/publish but don’t let that annoying detail inhibit your writing.
For now just write; your story can be catalogued later.
Here is a brief overview of primary genres. Glance at them and move on.
Action/Adventure: fast paced exploration with conflict.
Erotica: focuses on the sex, not the romance.
Fantasy: Magic other worldly, mystical and mythological.
Horror: anything that invokes fear/dread.
Literary Fiction: focus on the quality of writing style/prose over the narrative/plot.
Mystery: involves solving some sort of crime.
Thriller/Suspense: creates tension which can involve action or mystery.
Romance: love and intimacy without the down and dirty details of said intimacy.
Science fiction: think aliens, alternative worlds and high tech
Westerns: usually taking place in America’s ‘Old West’; cowboys, etc…
Women’s fiction: all about the woman e.g. growth and hope.

I just finished packing to head to Benton Arkansas for the weekend and I thought about the movie Sling Blade.
Sling Blade is a drama. No, there is not a drama category listed above because drama is written for performance. The paperback copy is categorized as screenplay. As a screenplay it is listed on Amazon as follows:

#1100 in Books > Humor & Entertainment > Movies > Screenwriting
#5851 in Books > Humor & Entertainment > Television
#26979 in Books > Arts & Photography > Performing Arts

Now allow me to detour a moment because I do love me some Billy Bob Thornton. I am also excited about visiting Two Peas in a Pod Flea Market and some dear kinfolks in Benton where Sling Blade was filmed.
Ahhh. I still cackle when my [adult] kids slip into character and quip, “fried taters, Mhm.” “With mustard and biscuits. Mhm.”

If you are familiar with the movie Sling Blade you’ll be familiar with this line, “Some folks call it a sling blade; I call it a Kaiser blade.” Yeah, I heard some of you saying, Mhm.
Well  I have a sling blade too (along with a few other tools) but I call it a limb-chopper.

People can call it what they want but that will not alter the way I use my limb-chopper. I use it to chop limbs — all sorts of limbs.

I call it what I want to; I use it however I please BUT if I decide to sale my tool… my merchandise, I will need to identify it properly and list it in an appropriate category.
See what I mean? Mhm?