The main reason I decided to make Android apps rather than iPhone apps is because I have an Android phone (makes sense, right?), but there are other pragmatic reasons that make Android more appealing to hobbyist developers like myself.
First of all, to post your
apps in the Google Play Store you have to pay a developer fee of 25 US dollars. This is a one time fee and once paid it allows you to post as many apps as you would like to the Google Play Store. Conversely, to post apps to the Apple app store, you have to pay a fee of 99 US dollars every year. While this isn't a big deal for larger developers, it is pretty unlikely for a hobbyist to make any significant money so a lower fee is going to be more comfortable.
While developing for the Apple app store might be slightly easier (fewer devices and screen sizes lead to less possible issues, Android's Java is notoriously bad at memory management, among other things), to a novice developer there won't be much difference at first. Also, this minor benefit is greatly outweighed by the ease of publishing on Android. Both app stores nominally review all apps that are posted, but Android has a much more lax set of standards which are easier for beginners (like me) to meet. This is good because as design novices it is very unlikely for us to create something amazing in our first go around and being able to see your app in the Play Store is much more motivation to continue compared to receiving a rejection letter from Apple.
Also, the Apple App Store has a policy of removing older, un-updated apps. While this is a reasonable policy, if you are creating apps as a hobby after your kids go to bed (like me!), it is a hassle to maintain all of your previous apps to ensure they meet future guidelines.
For these reasons, I think it is better to start out creating with Android. It is cheaper, it is easier to remain motivated, and your apps are likely to remain available longer.