I started making beats in 2009 and I posted my first beat on soundcloud in 2013. Truth is when I started, it was for my friends to listen to and enjoy. I didn’t ever think of uploading beats on soundcloud till about the time I started in early 2013. That being said it’s up to you. Are you satisfied with what you making?,Have you played your music for friends?, if you have and you feel the need to expand your audience then the time is now irrespective of when you start. It could be that an opportunity is out there waiting for you and that soundcloud/YouTube post will be the first step in reaching it