I never built the 40 but I did build two pt60's.  I love em.  Your attitude and excitement sounds great.  Your age is fine.  As someone else was saying, most guys are older due to the cost of this hobby.  But us oldtimers(52) love to see young guys into  it like we are.  Since you are officially a builder now, open a thread in the kit building forum and we will all help with all your questions.  Good luck!