I've heard quite often that a lot of people are frightened to do EMDR. It makes sense, you're going to be going to a lot of places in your head that you've been trying to avoid for a long time, and you'll have to face memories you've been trying to get away from or numb out. It's going to take a LOT out of you. I am currently 26, and went in to EMDR when I was 21 and finished up when I was 23.
My experience was that:
1). My therapist was amazingly compassionate, and very understanding of my experience.
2.) Before we ever even started EMDR, we established a "safe place" in my mind, where when I was processing and "seeing" my memories play out, I could just go to the safe place if it got to be too much.
3.) Notice something about yourself. When you have certain thoughts about your abuse or that stem from your abuse, you will have a feeling in your body somewhere. That's really important to pay attention to, because you're going to be making connections between those feelings in your body and the thoughts in your head. Your T will guide you through that all.
4.) When you find a thought and squarely and directly start processing it and remembering the events that gave you that thought, you're going to get slammed with emotion. You may feel angry, sad, frightened, whatever. What's weird is that you'll learn to tell the T exactly what you're feeling, and you'll watch yourself pour your guts out, and then suddenly, almost as if by magic, that event or that thought/feeling loses that negative charge. It might take a few attempts to get there, but I swear to god that's how it happens.
5.) You will likely get an "EMDR Hangover" when you process particularly difficult things. You will probably feel exhausted, or you may even feel triggered. That usually subsides after a few days, but you should be aware that it happens.
6.) Even after therapy, and even after you "finish" EMDR, you may still repeat old behaviors for a while until you realize what they're doing to you and how you feel negative about them. For me, once those realizations finally fell into place, I really managed to break free of those behaviors.
Ultimately, it's your call. I went into EMDR because I had a meltdown while I was at college, and I didn't want to spend the rest of my time in school being afraid of social interaction and being near suicidally depressed. It was kind of like a "you need to face this NOW or you're going to destroy your life or your future or something, but you absolutely cannot stay where you are now". The thoughts, feelings, and emotions I was experiencing were so bad and so intense that I could barely make it to class. I didn't want to be alone, but when my room mates were around, I didn't want them to be. It was awful. I don't know how you feel right now, but if you're going to do EMDR (and I highly recommend it), then you've got to be 100% totally and completely honest with yourself. A side effect of that is that you'll gain great insight and introspection about who you are, and I've found that I've been able to be much more open to the world and a lot less resistant to things that I used to be.
Progress is not going to be a straight line forward. You will have times where you make 3 steps forward and then suddenly you'll take five steps back. You'll have periods where you feel euphoric and alive, and periods where you feel despondent, like you're just sitting around waiting to die. Or you'll be in between those two, which just feels like limbo. Not depressed, but not happy either. It's hard, and it took me two years to process everything. I do highly encourage you at least try it though.