Several thoughts on this:
Your ADHD is making you massively over-think this.
Find other things to think about: how is the rest of your life? Friends, family, work and/or studying, career plans, hobbies and interests - your relationship status should not be the single most important thing.
It is just playing with words in the end, but to my mind "being in love" comes first, and "loving" comes later. You can "be in love" from first sight - it is all to do with projection, fantasy, limerence, lust, crush, obsession, and a whole load of stuff that is irrelevant to whether you actually know the person.
Real love requires that you truly know the person and it only deepens with time.
I think your BF has it back to front, but as I said, it is just playing with the definitions of words and it is not really important how you label it.
It doesn't matter when a BF says "I love you" - some can say it within a few weeks and it doesn't mean much. Some don't say it for years.
What really matters is how he treats you - actions speak louder than words.
You should not be talking with him about his previous girlfriends, let alone when he first "loved" them. That is just feeding your anxiety and is not healthy. His past relationships are irrelevant.
If he starts talking about them, or starts up these ridiculous conversations about how he feels and when he might feel this or that in the future and how he labels it, shut it down. Change the subject. Tell him that you want to talk about XYZ, or it is time to go and do ABC.
Show by your actions that you are not interested in playing silly mind-games and word-games.
Your fear of being hurt is understandable, but life and love are about taking risks. Just go with what you feel, let yourself be open to feeling deeply, and see how it turns out. Enjoy the process of dating and getting to know each other. That is all there is to it.