Generally. It alll depends on your medical condition. If you do not have fibroids or a pelvic infection or any condition that will contraindicate its application, it should be generally safe . You will need aa thorough gynecologic evaluation prior.
Yes. If the idea of having something inserted into your body and leaving it there for years freaks you out, you can rest easy: A new study published in the May issue of Obstetrics & Gynecology found that the intrauterine device...is a safe birth control method for women of any age, including teenagers. http://www.womenshealthmag.com/health/great-news-about-iuds.
Yes. Just as safe as for a 31 or 21 year old. Your doc will make sure you are a good candidate and if you later don't like it for any reason; it can be easily removed.
Yes. Iud are safe if used by the proper patient. Pt's who have multipe sexualy partners and are at risk for stds should never use an iud. If you have an uterine anomaly this could also be a problem.