Yes, you can start fires with uncontrolled currents. This is what fuses are for. Also what my sibling comment said; start small, blow up small things by making

Yes, you can start fires with uncontrolled currents. This is what fuses are for. Also what my sibling comment said; start small, blow up small things by making mistakes (like putting a transistor in the wrong way around and pushing several amps through its inherent body diode; we've all been there), and then you'll be confident enough to start playing with actual power electronics (if you want to). What you'll find though is that, as a result of everyone before you making the same kinds of mistakes, there exists protection circuitry for almost everything you would want to do. For example, Lithium-Ion batteries are quite unsafe if you treat them without the respect they deserve, but that's what e.g. the DW01-P IC is for, and many Li-Ion charging ICs feature NTC thermistor inputs (e.g. the LTC4053) to stop charging if the cell is outside of some safe temperature range. If you're really worried, a CO2 extinguisher and a bucket of sand go a long way.