Am I beginner, intermediate or advanced? How can I tell what my level is?

This is a challenging question because the answer is subjective! However, here are some general guidelines as to what your skills would look like at each level.

At the beginner level, you should range from having no knowledge of guitar, to being able to play through basic open major and minor chords and change between them smoothly while keeping a few simple strumming patterns going. It is also good to have some basic lead guitar skills like being able to pick out a simple melody or scale. 

At the intermediate level, you should be able to do all of the above and have the ability to play bar chord shapes up and down the fretboard, and you should know your basic 7th chords. At this level, you should be able to play through any basic strumming pattern, and use the chords and strumming patterns you know to play along to simple songs with no problems. For lead guitar, intermediate players should have the ability to play through and use at least one major, minor, minor pentatonic, and major pentatonic scale to improvise and write solos or melodies. You should have a basic understanding of music theory and keys.

At the advanced level, you should be able to play all foundational open chords, bar chords and extended chords (7ths, 9ths, 11ths, etc.) everywhere on the fretboard as they relate to the CAGED sequence. Picking out strumming patterns in songs with no problem is a must for this level. A deep understanding of music theory and how major keys work is also important. You should have a high technical ability, and be able to play through and improvise with arpeggios and scales including all 5 major and minor pentatonic shapes, all 7 3-note-per-string modal scale shapes, and all arpeggios and scale shapes in the CAGED sequence.