When should I tell my company I plan to leave?

I started working in the ABA field as a BT in January and have thoroughly enjoyed learning about the field and the work that is done. I think I want to pursue a Master's next year and begin working towards my BCBA, but the company I currently work at did not provide many resources when I spoke about that being my goal. I sort of stumbled into another company (a friend of my dad's works for their parent company more on the cooperate side) that ended up offering me a position and have already been so helpful in regards to planning a future in ABA. While I was talking to that company I was also provided an incredible opportunity to get a 200-hr yoga certification at a 3-week program out of the country. I honestly cannot believe how nicely everything has worked out, as the new company said they would still give me the position with a start date in late May, meaning I will be able to work at my current company until early May, get my YT cert in May, then start at the new company once I return.

That being said, when should I tell my current company that I plan to leave? I want to do what is best for my client, which I believe would mean informing my BCBA/ management as soon as possible so they can begin to create a transition plan, but I have never quit a job and I am worried that if I tell them too soon they may ask me to stop working before I leave, which would not be good for me financially. Should I just wait until mid-April and give them a standard 2-week notice? Or should I begin communication sooner? Would it be inappropriate to have this conversation with my BCBA, without getting management involved yet?

Thanks for any advice you may have!