Before you think about changing cues, learn about how deflection works and how different shafts affect your play in general. That is the only real reason to "upgrade" past wanting something different looking. Cue length, hit feel and balance are bit parts of the equation of a full cue but ball pocketing is all in the shaft. Find some people with different cues and shafts, have someone explain to you how aiming and deflection works. Then find something you like. Without trying maybe 10 shafts/cues it will not be easy to form your own opinion on what to get.
IMHO for someone that knows they will stick with the sport, there is no such thing as a "beginner" cue since you are going to be learning to play with the shaft you have. Since the shaft you use will affect how you aim, you don't want to be changing shafts around as you get better. It's not like a sports car where you want to learn to drive well before getting into a 600hp rear wheel drive car. A fancier cue with a good shaft you like won't make you mess up any more or be harder to control.
I suggest people start out with a good low deflection shaft to learn with from the start so they don't need to spend a lot of time learning to aim with side spin, but also get knowledge about the cues in genera including standard ole shafts. Just going up to higher quality or more expensive cues just for the sake of paying more to get a "better" cue is no good.