Look at renting one on Turo for a weekend. That's how I tried it out. I personally find the model 3 more than big enough for my family's needs. I helped my daughter move and it was great with the seats down. I rarely have more than 2 in the car plus dog (she loves dog mode)
You can try the 3 and the y out. the model y would probably not fit in my garage.
Thanks for all the great responses everybody. Seems there is lots of different thinking on this! The consensus looks to be it will probably be great for me but I won't know till I put my butt in it, drive it around, and see how I feel. Got an overnight test drive scheduled for this week when I'll put the car through it's paces and see how it works for me. Hoping for the best. I do really want the Y but also need to make a sound financial decision. I'd rather have a Tesla that's 80% of the type of car I want (SUV vs. sedan) than an non-Tesla SUV. Fingers crossed!!!
Will be interested to hear after your test drive which option you decide on. I have a Model 3 and am very happy with it (9/2018). I occasionally miss the hatchback that my husband has on his MS but for 99.9% of my driving my Model 3 it's not a real issue. But lifestyles are different and I don't have a dog or kids at home.