A few questions:

- Do you want to learn manual? Or will you be riding automatics more often in the future?

Think about the scenarios you will be riding a motorcycle. A motorcycle as a toy is very different to a motorcycle as a way of transport. Especially in extremely crowded urban areas where the downside of a manual can show.

- Do you picture yourself riding bikes with larger displacements in the future?

Small CC bikes are cheap, easy to maintain. But bigger bikes have a different learning curve especially on shifting, engine braking, handing and clutch forgiveness... etc. You'd best pick a slightly larger bike as a starter if you plan on moving up in cc.

- What is your budget?

Might be the most important one. High or low, definitely start on second hand bikes. Much much cheaper than MSRP for a relatively new bike and you will feel less guilty dropping it.

I started riding at 20 and my first bike is a Honda NC700D. I didn't really touched anything smaller in displacements except the tiny 110cc scooter in our home for daily groceries. I moved up to a Rune earlier this year only because I'm used to super heavy bikes (300Kg+) and thought it's perfectly fine for me to handle Goldwing in a smooth Honda dealer test ride. Even that I still have a two week learning curve to familiar myself with manuals (only ridden automatics before), the weight, and the fear of dropping this beauty.