Yes, in today’s competitive climate 1.5-2 years is a minimum for a competitive clinical psychology application. You also need to have an area of research identified that you want to investigate, and find programs where you fit in. For example, if you want to do research on mood disorders in low-income children with autism, you’d try to find a department in which some faculty members (2-3) are doing some research in that area (maybe someone’s doing exactly that, or maybe someone’s doing research in mood disorders in children with autism and you add the low-income angle, or someone’s doing research on mood disorders in low-income children and you add an autism angle, or someone’s doing research on mood disorders in low-income children with other developmental delays).
Some people get into clinical psychology programs straight from undergrad; if you do all of the projected clinical volunteering/intern work and you do actually start doing research this fall, you are one of those candidates that is competitive for admission directly into a PhD program. However, it’s increasingly common for people to take 1-3 years between undergrad and grad school to gain additional research experience, usually as a lab manager or (often paid) research assistant in a university psychology lab or one in a related field (psychiatry, public health, education). I don’t know what the breakdown is, but I’m betting it’s at least 50-50 (half people who came straight through and half people who took time off) and it might be more than that.
So yes, you’re on a good track - there’s nothing wrong with your track, it’s simply that the field’s so competitive these days that you might need to take some time. Taking time is good, though, as you can figure out what it is you really want to do in the mean time by getting some good full-time experience in research. (For example, you may decide that your needs are better served by a PhD in school psychology or an MSW - not saying you will, but it’s a possibility.)
One last thing. I’m not sure what your goals are - whether you want to do clinical practice in the field, academia, or a bit of both. But I will say that most of the top tier programs in clinical psychology are clinical science programs; that means they are mainly concerned with conducting research in the area of clinical psych. As Berkeley describes it
"[we] conduct translational research in which we study foundational mechanistic processes…with the goal of better understanding and ameliorating human problems… The treatment research we conduct is used to develop hypotheses about and/or confirm contributions of the foundational mechanistic processes, and it also contributes to improving treatments for important human problems and in diverse populations.
Berkeley’s PhD program’s main goal is turning out researchers and academics. While they are APA-accredited and they do train you in the basics of clinical practice, what they would really love is for all of their graduates to become professors at other top clinical psychology programs.
If your true interest lies in direct clinical practice with children, you may want to seek out a scientist-practitioner program that focuses more heavily on preparing clinical practitioners instead of academics. There are lots of excellent and highly-regarded programs that do that - it’s just that the tippy-top programs in clinpsych tend to be clinical science focused.
Here’s a list of clinical science programs through the Academy for Psychological Clinical Sciences: https://www.acadpsychclinicalscience.org/doctoral-programs.html