A few months ago my car stopped starting

If the engine turns over then this is not the starter or theft system. This is an air, fuel, compression, spark issue.

So, we need to start crossing these off the list.

I doubt this is a compression issue because nothing happened to cause an issue there so let's come back to that.

Let's start with fuel and then spark. Here is a guide that will help with fuel pressure.

https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator

If you have pressure, then we need to pull the spark plug and crank the engine to find out if we have spark.

Here is a guide that will help with this:

https://www.2carpros.com/articles/car-cranks-but-wont-start

Please run through this info and let me know what you find. Thanks