Yep, you can complete only an Associate's degree (two years of college on average). Most jobs that require a degree require a Bachelor's degree or higher (four years of college on average), but there are a few that only ask for an Associate's degree. It depends on the job listing and company. To be a teacher, you need to have a Bachelor's degree or higher, no exceptions.
Also, an Associate's degree is typically very generalized. It's basically just your core/general education classes (writing, history, science, math, ect). Whereas Bachelor's degrees or higher contain both general education classes and classes specific to your specialization/major. I don't have to start from square zero though thankfully. All my classes I completed as part of my Associate's degree can be taken into consideration while getting my Bachelor's degree. So, I completed all of my general education classes already, and now I'm focusing on taking classes specifically for teaching. An Associate's degree can also help you work towards any major, not just one or two in particular.
Associate's degrees are almost exclusively earned at either an online college or a community college, both of which are MUCH cheaper than an in-person, four year university. The tuition is cheaper, so it can save you money. It also let's you have another degree you can list on an application, and shows you have some college experience, even if you don't have a four year degree just yet. I got one because I had been in college for four years and wanted to have some sort of degree. I still needed another two to three years for my Bachelor's degree at the time (I was going to college only part time, hence why it is taking me so long). So, even though most people already have their Bachelor's degrees by the time I got my Associate's, I figured I had been in college far too long, and I wanted some sort of degree by now to celebrate. It also made transferring to a four year university much easier.
An Associate's degree is ideal for people who are poor and struggle to afford college, and for those who know they want to go to college (either to get a degree, or for the "college experience"), but don't know what they want to study yet, or people that want a general degree instead of a specific one. They also have much higher acceptance rates than most colleges, and can be good for those with a low GPA from high school, or who got rejected from other colleges they applied to.