I don't think that you are hothousing, you and your son seem to be having fun - a particular family version of fun, but fun nonetheless.
I would get the testing, because having guidance one can trust is a wonderful thing. You are so lucky to be within driving distance of
http://www.davincilearning.org/ Aimee Yermish
30 Carriage Lane
Stow, MA 01775
(978) 461-4815
aimee@davincilearning.org
www.davincilearning.orgI would recommend to call her and say what you said here about your concerns. Also - go observe some Kindy classrooms and 1st grade classrooms.
With gifted kids the academic problem with school can be though about as
1) level
2) pace
So even if you were scrupulous about not introducing 'school topics' with your son and he didn't know how to read one letter, he could still need a gradeskip because the pace might unhinge him. You seem to be intuitively aware of this.
Public schools can be good places for kids of all LOG (levels of giftedness) but that requires someone (often the parents) to do some fancy footwork (advocacy) and be flexible (asking for whatever gradeskips and subject accelerations are needed to keep school fun and satisfying.
I would also ask Aimee for suggestions of social events where your son (and you and DW) would get chances to hang out with 'true peers.' I believe that it is good to have a wide variety of friends, and that variety comes in many flavors, but that finding 'true peers' rather than agemates is an important part of that mix. Depending on where one lives, this can be quite a challenge, and need some careful planning.
funny story about that linguistic ability - my son, now 13 also had that amazing linguistic ability, and lawyer-like mentality. In 2nd grade, one of the staff at his school treated him unfairly. He called her a 'hag.' He claimed that he didn't know what it meant, but that it just slipped out. He was duly punished, and became more thoughtful.
Bottom Line: Develop a poker face, because it was very funny, and I didn't dare laugh.
Love and More Love,
Grinity