Fasting

Hi! I am new to keto ( started 9 days ago) and had a question about fasting. Do you have to start fasting right away? I suffer from migraines and that is the only part I am worried about. I haven’t had any migraines since starting, actually have been feeling really well, I think it’s all the water I’m drinking, close to 100 oz a day. I also have Ultima as an electrolyte supplement, so I feel good! 

I wonder with just starting out, I stop eating at 730 and won’t have anything else until 630-7am the next day, can that count as a fasting period first at least? 

If not, how can slowly add in fasting periods, can you do like 3hr or 4 hrs increments? 

Thank you you so much!