W.L.
Hi A.,
We let both of our boys sleep with us for a little over a year each. It is definitely a matter of convenience, as well as the fact that I just think it's more natural for infants to sleep at least in the same room, if not in the same bed as me. However, it does cause for a major challenge later in their life when you are ready for them to sleep in their own bed, as you're experiencing. As a new mom at the time, I was finally convinced with my older son to cry it out in his room, which eventually worked, but it's just not something I personally believe in, so I'm not taking that approach with my younger son, who I'm still "crib training". It's been a long gruling process, but I've picked up a few tricks along the way - some of which may still apply to your 3 year old.
Getting them to sleep in their own space in a healthy way is a matter of them being comfortable and feeling safe where they are. At almost 3, you should be able to talk to her a little more than you would an infant about sleeping in her own bed. Setting the expectation is KEY in any part of parenting, even if they don't completely understand it. Setting a consistent bedtime routine is also something of comfort when going to bed, which helps to make the environment feel secure. Including a good bedtime story or two and spending some cuddle time in her room with her when she's going to sleep will likely increase that security. Also, if she doesn't have one already, you may want to try to get her attached to a "Lovey", which could be a s stuffed animal, or blanket or something. (I think as long as the Lovey stays in the bed, and doesn't become a security thing for life, it's OK.) If you wear or wrap the item around your body for 10 minutes or so before bedtime, it will smell like you, which is really comforting. You can also try to play some really low volume soothing music or heartbeat sounds. They're more for babies, but they work on me, so I'm guessing they might help your daughter as well. Another thing that helps with babies, that might help with you is to load her up with food and attention during the day, so she's not seeking either at night. Keep a glass of water by the bed if she gets thirsty.
As an additional note, if she's waking up crying in her sleep, that's likely what's called Night Terrors. Both of my boys have it as well, and it is quite disturbing. My older son (4 yo) hasn't had it happen in a while, but my younger son (18 mos) still deals with it from time to time. One theory behind it that I've found mostly accurate is that they get it when they aren't getting enough rest during the day. It may be a security thing as well. If you're not familiar with it, you should look into it more, but just to give you some general pointers - don't try to wake her up when she's going through this. It actually makes it worse. There's really nothing you can do to stop it, but you can try to comfort her as much as possible, just by whispering "mommy's here...you're safe...you're OK." The episodes usually last anywhere from 5 - 15 minutes, but I've found comforting helps a lot. I've also been told to turn on the lights, as shadows can be very scary, but I've just been careful about my shadow. If they don't wake up, they won't remember it in the morning.
I hope that helps! Take care and good luck!
(PS: Never apologize or be defensive about how you choose to parent. Everyone has their opinions about everything. Whatever you feel is right for your family, IS what's right for your family.)