I dont have any experience with toilet training at 12 months, as we have only just started the process with our almost 2yr old daughter. However, I have been doing allot of reading up on the subject. I think toilet training so early must have been the done thing back then as afew people I know were trained by 12months 30 or so years ago aswell. Regardless of what your mum and MIL tell you, you have to do whats right for you (as they're not the ones who have to do it).
The general advice I have foud on the net and in various books is to start training when your child shows most of the signs of readiness and not before. It is a lot easier to toilet train if your child is both physically and emotionally ready.
Some ways to identify if they are ready is if they can understand what "wee, poo, dry, wet, clean, dirty and potty" mean, can follow simple directions like "lets go to the potty and lets you know when she has a dirty nappy.
Some other things that will help the process along would be to get some books you can read together about going potty, and investing in a doll that can wee - everytime dolly does a wee on the potty, throw a huge party and show your daughter this is what happens whenever she successfully uses the potty.
As for training pants (if u mean pull-ups), I didnt find them to be useful at all, as Jaida still thought of them as nappies. If you can stand cleaning up the mess for a while, they do tend to train quicker by going staright to undies as they can feel the wetness much more.
Anyway, just remember that toilet training should be a fun and exciting experience for both you and your child.
Hope this has helped - let us know how u go.
Jaida (6), Ameli (2) & Lacey (2mths) - SA