Go for it, girl!
Do you know WHY your pH was off and have you solved that to your satisfaction? Can you repeat that solution each and every time you change the water? (I have WEIRD water and it is a struggle, too, so I feel for you!) Get the fish!- There is nothing like a wonderful new fish to inspire you to make that tank pristine!
Your tank (US gallons, not the other?) is plenty big enough that any changes you cause will happen much more slowly than in a 20 gallon so you should be fine.
Realize that when you put your first two fishes in you will get a bump in the cycle. You need to have the tests to watch it and the water to fix it. Prepare for this. (I find myself gathering water about 20 hours a day in prep work!) When that bump is done, you can add more fish. But if there are three there at the store saying "TAKE ME HOME PLEASE!!!!" then I say go for it!
(Do you have fish in the tank already? If so, there should not be a bump, but you should quarantine the new ones elsewhere. By the time they clear quarantine you should have absolutely NO questions about your tank quality - it will be SPLENDID!)
I am sorry that your pH has been so much of a struggle. I have to admit that there was so much info flying around that my head was swimming with the fish! I am glad you have it all straightened out!