Learning curve for After Effects

The UI and workflow is pretty complex. It's kind of like Photoshop, but you'll need to spend several hours just going through the basics before you understand how things work and how to troubleshoot problems. At the very least you should open up AE and go to the Learn link on the Home Screen or open the Learn workspace and spend 20 minutes going through the guided tour of the UI and the first project. 

Just downloading templates and trying to customize them as a way to learn AE is a pretty bad idea. About 1 out of 10 templates are easy to understand and modify. Most of them require a lot of digging if you want to do anything more than replacing an image or change some text. Way too many templates come with no instructions or user guides.

You'll also want to spend some time with the User Guide. A link to it is always on the AE product page, on the home screen, and on this forum. The Search Help field in the top right corner of AE provides a better search for answers to most questions than any of the standard internet searches because most of the content has been vetted. It will also lead you to the online documentation. I don't want to discourage you but it is not unusual for someone to spend 40 to 100 hours learning about AE, compositing, and animation before they can handle anything more complicated than following some recipe they found in a tutorial on YouTube. Speaking of YouTube and online training, most of the tutorials you will find on the net have been prepared by enthusiasts that don't really know how to explain things, have poor workflow and organizational skills, and a huge number of them will only work if you using the footage the presenter is using in the tutorial. You have to vet your trainers and make sure they know what they are talking about. Probably 80% of the problems folks on the forums are having following tutorials are caused by poor explanations or inefficient and sometimes completely wrong workflows. Be careful with you look for tutorials.

Learning how to create compelling and effective animations and motion graphics is also a lot more than just learning how to set a few keyframes. If you are interested in learning about animation of any kind including motion graphics investing in The Illusion of Life: Disney Animation by Ollie Johnson and Frank Thomas will be a great investment. That is the best source I know of to teach you how to make animation really work. There are similar books on Compositing and Visual Effects that are very helpful. The tools may be different, but you need the same masking, blending, layering, and understanding of color and light to do a successful visual effect no matter what software (tools) you use. 

I often share this graphic comparing After Effects and Premiere Pro. The same can be said for AE and Photoshop. With a little training almost anyone can learn to take off and land an airplane, but if you get into even the tiniest bit of trouble with After Effects, you better have done your homework or you won't even be able to put down the landing gear. There are very few one-click one-button solutions in AE.

The learning curve for After Effects depends on your background, it's not bad in my opinion. Best way to find out if you like it is start a free trail and go through some free tutorial online or paid ones with Pluralsight, School of Motion of similar sites.