As a zwds astrologer (a kind of Chinese astrology), I see these star positions and planetary angles as a measure of time and somehow the time of our birth have something to do with our destiny or life path.
For me, it is NOT the common belief that the stars in the sky CAUSES who we are but instead our life circumstances changes with time, and movement and positions of these celestial bodies are the best indicators of time. They're constant, always keep moving at an pretty unchanging rate. They're measurable, unlike time itself, we can use units to gauge time.
If you're good with maths, this might help you understand. I see destiny (or what's going on in our life) as a function of time, which means when times changes, our destiny at that time changes accordingly with a pattern too. And astrology is a tool of decoding of that unknown pattern.
To be honest, if you practice astrology for a certain amount of time, the magnitude of real examples and extent of accuracy you've seen would just be more than enough for you to trust it and know it's real. For exampe, if the Sun is the life palace, and it's bright in the palace, the person would have qualities such as warm, helpful, kind, forgiving and good with speaking & expression.
Maybe if you stop finding a way to convince yourself stars have an impact on you and start studying it, you might see a side you've never seen before :)