Hey,
I am doing electronics since 2 years, and Im 16 years old - so you understand that I dont really have a lot of knowledge.
I have practice in basics, from Mosfets to Resistors, but my practical knowledge ends on OpAmps, Inductors and Optocouplers...
I kind of got the theory, but I dont know how to use it properly.
But..
I got quite a big project goign on

and I need some help, please.
I am building a Vape Mod that is basically measuring current and voltage and adjusting it with a mosfet that is controlled by pwm with the Atmega328p.
The PWM Frequency doesnt need to be high, but I dont know how much I need. It will be under 1kHz.
My Question: is the schematic okay like it is? Will the Mosfet handle currents at around 30A or more without cooling (Pulses of 5s every 10s)?
And now my big question.
Between the Drain of the Mosfet and A- (Atomizer -) is a shunt resistor to measure the current. I want to read out the Voltage of the shunt to get the current reading.
But now the problems: the voltage is too small to read properly. Can I use an OpAmp?
Second problem: When I measure between ground and A- I will get the voltage drop of shunt and mosfet together. How should I measure just the shunt? I need to galvanically isolate it to measure, right?
Thank you really much for every help, and sorry for taking up your time!