Obviously I can only share what I've been taught but am worried I'll confuse you. Do read up and look for a teacher you feel happy in you can talk to about your concerns before starting.
I was taught in the guidelines that for trimester one you can practice most things (as long as they feel ok) but twisting especially is not advised as the placenta is forming and establishing itself in the abdomen and therefore it's not a good idea to compress and twist the abdomen at this time. This would be any twists - seated, reclining or standing twist poses. I am specifically talking 'twist' poses here. There are, of course, poses like trikonasana that are categorised as standing poses which have a twist but this is in the upper body so as long as it is isolated to the rib cage or above - it's ok.
You can do inversions and head stands in the first trimester if they are a firmly established part of your practice. The caveat to this though is to listen to your body and if they make you feel queasy your body is telling you something. Similarly, if you suspect you have high or low blood pressure then don't practice or any fainting/dizzy spells.
Beyond trimester 2, some women do carry on with these but you should avoid strong abdominal work from trimester 2 onwards so you need the advice of an experienced teacher for this who knows your practice well if you want to even think of continuing that type of pose. I don't. I'd rather not take any risk.
Backbends beyond tri 2 depend on your pregnancy may be ok depending on your practice but I have a 12 year daily practice and my teacher has suggested I don't do anything that may compress the lower spine now (backbends can) and now is a time for leg strengthening and shoulder strengthening and opening.
Obviously as you get bigger then lying on your front poses and forward bends are not advised, although you can do may poses with a strap and stay upright. You will also need to lie on your left hand side from about 20 weeks to be safe and not your back to avoid compressing the vena cava and interrupting the blood flow to yourself and the baby. No savasana on the back.
Given your age and concerns, I'd really suggest, as you're going back to a practice after a break, that you find a good teacher you feel confident understands pregnancy and read up for yourself as well as listen to your own body.
It can all be a bit confusing and I don't want to give you too much information. Find a teacher you feel confident in and they'll look after that for you so you can just enjoy the yoga.