I am the mom of an 8 month old, with another one on the way. SIDS is definitely a scary issue. I still check my son at night. Ok, somethings to prevent SIDS, I am taking this from a book titled: Your Baby's First Year, second edition, Steven P. Shelov, md,ms,faap, editor in chief. I have found this book extrememly helpful and also the book "What to Expect your babies first year". But please discuss this issue with your pediatrician too.
Anyway, place your baby on his/her back to sleep. I placed my son either on his back or on his side. To keep him on his side I placed a small rolled up towel behind him, for the length of his body to help keep him on his side. This is how they brought him to me in the hospital so I kept it up at home. We would alternate sides that he slept on. It seems the back and side positions are safer than prone(on their stomaches) The books states "Both back and side sleeping positions have a lower rish of SIDS than sleeping on the stomach." The book also states that "placing babies on their backs applies to infants throughout the first year of life. However, it is particularly important during the first 6 months, when the incidence of SIDS is the highest."
It is also important to "avoid placing her on soft, porous surfaces such as pillows, quilts, comforters, sheepskins, or bean bags-even soft materials used for stuffed toys." "No waterbeds, sofas, or soft mattresses." "A firm crib mattress covered by a sheet is the safest bedding."
Keeping her/him in a swaddler is fine, it will keep him/her warm and reduces the risk that a blanket will present by riding up and covering his/her mouth and nose. I used to use a very thin blanket on occasion that I tucked firmly around the mattress. But just make sure the temperature is not too hot/not too cold and a swaddler is needed. Also try to keep your baby upright after feeding, get a good burp or a couple this helps them sleep better and prevent spitting up. The first night you will probably not sleep...we didn't, we were watching him breathe...its scary but they are so beautiful.
I don't think age is a factor. I am 38 y/o and had my first at 37. I did find the two books I mentioned earlier very, very helpful. I found that I would read them as I was waiting for a call back from the Pediatrician and he would say almost exactly what the book had suggested for treatment etc.
As I said before I still check my son everytime I get up during the night. I had tried a sleep positioner too, this is a "wedge" that the baby sleeps on that helps hold them in a certain positioner. If you get one I suggest getting one that is very breathable, mesh-like so if they do turn over the material allows them to breathe. Once my son was 5 or 6 months old however he rolled right over the wedge and back to the store it went...now he sleeps on his stomach and if I turn him over he goes right back. So I don't fight it, he seems to be doing fine.
Good Luck Swaddles! I hope this helped.