Yoga is not one size fits all. There are options for everyone depending on your needs and wants.
Hatha
This is a good beginners class and is usually slow pace. Many would consider it the general term where a lot of other types of yoga fall under. This class is usually 45 to 95 minutes of poses, breathing and meditation.
Vinyasa
Like Hatha, Vinyasa is a very general term that describes a variety of yoga styles. Vinyasa tends to be more vigorous than Hatha yoga. This style incorporates sun salutations. Sun salutations are performed to make sure that the body is warm and ready for deep stretching. Within this type of practice students "flow" because they are moving from one movement to the next.
Yin
This is another slow paced type of yoga. The poses are held for longer periods of time. For beginners they can hold the poses for 45 seconds to two minutes. While more advanced students can hold the poses for 5 minutes or longer. Yin is a bit different because it targets connective tissue, the fascia, bones and joints. It can also focus on some of the internal organs depending on the pose.
Restorative
This is yet another slow paced practice. Typically sequences for a restorative practice only consist of only five to six poses. Props are included as a way of helping you to rest and relax. So not be surprised if you fall asleep during one of these classes. The poses are held for five minutes or longer.
Iyengar
This practice was created by B.K.S. Iyengar, the purpose is to bring the body into alignment. Within this practice props such as yoga blankets, blocks, and straps are used to assist the students. Unlike Vinyasa students hold the poses longer.
Bikram
Also known as hot yoga because these classes are taught in rooms that can get as hot as 95-104 degrees. Most hot yoga classes are typically 75 to 90 minutes. In the hot rooms tight muscles are loosened and the profuse sweating helps you to cleanse yourself inside out. For must hot classes they are set to 26 poses. I would not recommend this for a first time student. Some studios over warm rooms as an option. This can help you to condition your body so that eventually you can practice in a room so hot.
Find what works with your needs and definitely check with a doctor to make sure that you can handle any or all of these types of yoga.
Be playful and explore!
Nasmaste