Ultimately, this has to be your choice, nobody else can make that phone call for you.
But I will say that for my DS, he is ahead of several curves, and behind on several others. He could read at 22 mos, recite and recognize the entire alphabet, and count to 10. His language skills were rated at twice his age. His fine motor skills were rated almost a year ahead of his age. But his gross motor skills were rated delayed. And his actual language usage was severely delayed - while he has a huge vocabulary, he lacked(s) the ability to actually converse, answer questions, or have any sort of reciprocal exchange. He's echolallic, which means he will repeat in great detail anything he has heard, from a random comment I make to reciting entire scenes from television shows. But until recently (after months of therapy) he couldn't tell me if he was crying because he wanted something or if it was because he had hurt himself.
I had ADD as a kid (would have been ADHD if that existed then), but did great with science/math and not so great with language, although I would read everything in sight from an early age. Ultimately that has little to no bearing on my DS though. Sure, it's something to note in his chart, that there is a family history of *something*, but there's no predicting anything related to delays and family history, so don't get hung up on that.
That being said, you're jumping directly to ASD, and I know here EI doesn't. The very first thing that we went through with EI was a general assessment. This was a meeting with a psych and a developmental ped, and they sat down and assessed him on all sorts of things, language usage, motor skills, behaviors, social skills, etc. THEY were the ones who first recommended the autism assessment (I hadn't even been thinking ASD), along with more detailed speech and occupational therapy assessments. If they hadn't had good reason for recommending further evaluations, the whole thing would have ended right then. Then we had 3 more assessments (over a few months), for speech, OT and eventually ASD. Each with a specialist in the field, each looking for their own little quirks. He had areas of delay for both speech and OT, but ultimately the ASD Dx trumped them both. But I was told by the assessing doctor that because of his advanced ability in several areas, he may very well no longer be considered ASD by the time he enters school - once we can work through the speech/language problems. And that would be wonderful, if the work we do now can make that kind of difference.
Ultimately, all the studies show that the earlier you start any needed therapies for delays, the more effective they are. So putting them off indefinitely just because you're afraid of the label seems a bit self-defeating to me. And you also have to keep in mind that none of this is instantaneous. It took 3 mos for us to get an ASD dx from the time I made the initial phone call. Then it took another 2 mos before we could start therapy. Which means that all told we only get 8 mos of intensive hands-on therapy before he ages out of the system and gets turned over to the school district. Even though I started the whole process before he turned 2.
I'm not sure what the pp's experience of ABA has been, but for us ABA has been entirely play-based. We also meet with his therapists and his team lead on a weekly basis to discuss any concerns that may have cropped up, anything *I* want worked on, what the therapists may think needs work, the direction we need to be heading, reward systems, any changes that need to be made to our approach, etc. I have the right to fire the individual therapists or the team at any point if I'm not feeling like it's helping matters. But for instance, right now we're working on potty training, and that's trumping everything else, because that's a skill that he really does need to have. But we're also expecting another baby any day now, and when he/she arrives, THAT is going to take precedence (they've been working on things like "gentle" up to now), as they start teaching him how to interact with the baby. These are *my* choices of what he needs to work on, because they're the areas that impact me/the family the most.
So really, I'm not sure what you're afraid of, other than the label, which can admittedly be scary. But if you ignore the warning signs and in another year have to make the phone call anyway, are you going to kick yourself over the wasted time?