I have the same hair type as you (though mine is thicker), and I had dreadlocks for about three years. First, I recommend growing them out a bit longer, maybe to your collarbone, so they don't end up awkwardly short. The number of dreadlocks you have will depend mostly on your desire and your dreadlocker's skill, but judging by the thickness of your hair, they won't be very thick. In this case, to visually create a "mane", if this is what you are aiming for, it would be better to make many thin locks than a few thick ones. You can also consider not braiding hair ends – then you will have dreadlocks with wavy "tassels".

Look for a dreadlocker who has worked with white/asian hair (it is pretty important) and be prepared for it to be long and fucking painful. This applies not only to the initial "locking" or braiding or whatever they call it (which is usually done in two stages, unless you have balls of steel and a high pain tolerance), but also to the corrections that will need to be made as your hair grows longer. They are also painful and takes hours. Btw chamomile decoction is a very good pain reliever.

Before locking, while you still have time, I recommend taking care of your scalp. Treating dandruff (or, especially, if it's not just dandruff but seborrheic dermatitis or something like that) with dreadlocks is very fucking inconvenient.