Some say, when you want a kitty, ask for a horse. So I came out as a wolf then, being non-straight didn't seem nearly as bad to them.
(that was a joke but has truth in there too);
You could gauge their attitudes about such things FIRST. Otherwise, you might not like the results. Don't set yourself up for horrible rejection. Either way, it's going to depend on them. You know them best. You do for you. You could be embraced by family or, you could lose them entirely. To say otherwise would be blowing smoke.
There are many very good books on the topic.
The Guardian top 10 books about coming out
PFLAG also has reading lists.
I highly recommend seeking out LGBTQI+ Center in your city/town. They often have in person support groups and/or libraries/loaners, book lists. Also, if possible, work with a counselor. They help you process your stuff not give you answers.
In my mind and experience (have run a number of support groups for many years and come out over and again) reading a good books takes you down a path in your mind where you can feel the author's story. Support groups are good but remember that everyone is at a different place on different, yet similar, paths. Don't follow their path but we can learn from each other.
BTW, coming out is a never ending process. I feel like I will be me and come out when I want, to who I want or not when not safe to do so. If other people find out, I can't change how they feel about such things except to be a model "me."
My reminder is that you are going to share this with them (perhaps) and they have not had 1, 3, 5, or your entire life (28 years or whatever your age) to come to terms with this. It will take some time if it's completely alien to them.
In a training seminar weekend a number of years back, a presenter (I'll call him Joe) was discussing at-risk youth asking what groups might come to mind. He was shocked when I answered LGBTQI+ kids as no one had ever answered that and he'd have to tell them. Of course, it's the FIRST thing that comes to mind for me. He is LGBTQI+ (and many people STILL don't know he is which is even odder since he's married to another guy). Later Joe came up to me and said, "OMG, you?" I just said, "Clever man...yes, we're literally everywhere aren't we" (He's a LPC). Lesson is that people don't see what they are not used to being around. Joe was used to looking straight for the general population and saving the other parts of himself for when it is safe (professionally and personally) that he wouldn't have seen me in a million years until I lifted up a corner of me to show him.... I did it on purpose as the group was a bit too white-washed & religious for me.
Sooner was better since I handle cases with LGBTQI family components.
In other words, if you've been good at keeping your family in the dark, they might not see this coming at all. They'll need processing time and you're going to have to be patient.. yet if it's important, not let them just sweep it under the carpet with the other elephants in the room.
Have a plan, have a support system, do what feels best in the moment..