The most glacial of progress XD
Blender will run on a Macbook Air spec'd laptop as long as you stick to low poly/simple models (I speak from a lot of experience x_x) so if you have at least that you can start learning now (there's at least four of us that can help you if you need it ;D) and then when you get your good PC you can make amazing things :D
The dilemma of every 3d artist with a budget setup.
I can start now but will i ever finish and render it?
Nahhhh
You'll finish and render something when you find something worth finishing and rendering.
Meanwhile there's so many skills you can be learning.
And also so many frustrations to be had when you actually hit the limit of your hardware rather than your skillset XD
I will turn into bone and dust before that time will arrive.
For now imma just draw ANIME WAIFUUUUU!