Rear facing is 500 times safer for a child, any child. Even adults are safer rear facing, but its not usually possible.
A childs spine does not ossify until 3-6yrs of age. Until that time, there is nothing but soft tissue holding the spine to the skull. Think of it this way, if you put a twizzler (the spinal cord) into a spiral phone cord (the spine), and hold both ends and give it a yank, what will happen? The twizzler (spinal cord) will snap, and the phone cord (spine) will stretch. The spinal cord can only stretch approx 1/4" before it snaps. But the spine can stretch a few inches. When the spine ossifies (hardens) to the skull between 3-6yrs of age, a childs chances of internal decapitation reduce greatly. However since you cannot tell exactly when your childs spine will ossify, its best to keep your child rear facing for as long as possible.
These are not new recommendations. EVERY car seat manufacturer has recommended it for years, the NHTSA has recommended it for years, and AAP has recommended it (and made an official statement last year) for 10yrs. This is not new information, but its becoming more well known because people are researching, actually reading their car seat manual, access to the internet, and they are learning to do better.
The AAP recommends children remain rear facing for as long as they fit into their rear facing convertible car seat, or at least 2yrs and 30lbs. Yes, we all know the law is 1yr and 20lbs, but that law is horribly out of date and it takes YEARS to update laws. Look how long it took to pass the new booster seat laws.... at least 8yrs in many states! Besides, I don't need a law to tell me how to keep my children safest, when you know better you do better and right now its very well known that rear facing to the max is safest.
Convertible car seats in the US will rear face to 33-45lbs (depending on model). A rear facing car seat is outgrown when the child goes over the rear facing weight limit or there is less than one inch of hard shell above the childs head. Feet touching the seat ,crossed legs, these are NOT a reason to turn a child around, and there has not been a documented case of broken legs in a rear facing child. In fact, the most common non threatening injury to a forward facing child in a crash is.... broken legs!
In a rear facing child in a crash, the car seat holds the childs body, cradling it into the seat. In a forward facing child, the head, arms, and legs are thrown violently forward. The difference is astounding, and even in a minor collision it could mean life or death.
Sure, a child is 'fine' forward facing... until a crash. Its not worth the risk. IF your child is still within the limits of her convertible car seat for rear facing, leave her that way! Especially in a van where you have tons of room!
My youngest rear faced until 35mos in a Britax Marathon. He was 35mos old, 33lbs, and 42" tall when he went forward facing. Certainly not a petite child, and he was perfectly happy. I have a Ford minivan, and I was of course easily able to get the seat installed in there. I was also able to easily get it installed into a Chevy Aveo subcompact without even having to adjust the front seat to make it fit rear facing.
Find a CPST to help you install it at www.safekids.org if you need help. But keep her rear facing. There is not one 'pro' to turning her forward facing until she outgrows the seat rear facing. You have an amazing car seat, use it to its potential.
Google 'internal decapitation', 'extended rear facing', and 'Joels journey' for more information on why to keep your child rear facing. Look for rear facing and forward facing crash test video's on youtube (they are a real eye opener). And if you have any questions or need links, please feel free to send me a message.