H.B.
I have owned a small car with kids and I can tell you it was so stressful and difficult compared to having my minivan....I admit that I NEVER wanted to be the mini-van mom, but now I don't know what I would do without it! You have 3 kids....two of which will likely start sports or other bulky activity soon (even school backpacks are big!)... I couldn't recommend a mini-van or larger vehicle more. Not only is it safer, but it makes travel, even for short trips to the grocery store, less stressful on you and on the kids-which would really be like sardines in the back :-)
I have a older Honda Odyssey and couldn't be happier....