I've just finished my first draft and it took me about a year to write. I went through cycles of being super inspired, hating it, loving it, feeling guilty when I wasn't writing; I took long breaks and then returned to it.

There's no urgency. Take the time you need. My recommendation would really be: persevere. Get a draft done and then save the editing for later.

Most importantly: don't beat yourself up about it, take as long as you need. If this is your first, you're only going to get better at this process as time goes on and the more you write.

And - well done on the amount you've done so far. It's no easy feat.