I've recently purchased my first ebike so am no expert. Because of stock shortages everywhere, I had plenty of time to research exactly what I wanted. I'm 5ft 3,but with a longer inside leg, so thought I'd be OK with an 18inch frame. Because of the additional weight of an ebike, I modified my choices. After trying a few normal bikes, I realised I'd need a smaller frame and wheels no bigger than 26 inches. I'm so pleased I took my time, as I may well have ended up with a bike that was too big for me. I had to discount several bikes because they were just too big,and I feel more secure being able to put my feet on the ground. If you can, try a few bikes for size, and see what you feel most comfortable with. I got a santana three from woosh, which I'm really pleased with. Hatti from woosh was very helpful and able to offer lots of useful advice. Juicy and wisper were also very helpful. Good luck finding the right bike first time.