At this time, is it possible for a beginner to learn bitcoin, where is it better, and which courses are effective?
As long as you have the zeal and you're sure you'll be consistent in your learning journey then you can learn Bitcoin.
Your starting time does not matter, there's a thought I always harbor in my mind each time I'm starting a new thing. "You might be new and yet still do better than those that have been there for years" just focus on improving yourself and don't let jealousy or depression get the better of you.
And I believe if indeed you're serious about your learning, with all the resources/links already provided in this thread should be able to enable kick off your journey and also to build a solid foundation in Bitcoin.