the more varied your types of fruit and veg, the better -they have different combinations of vitamins/minerals. the typical recommendation is for slightly less than half of your intake to be fruit.
didn't she ask you about your current diet before she started dishing out advice? Maybe she noticed the lack of fruit, so was trying to direct you towards a better balance?
Were you really eating 5 a day? Just because you knew it doesn't mean you were doing it, perhaps her challenge was to actually DO it and she picked fruit because it's more "instant" as it doesn't have the "preparation excuse" (in other word she was taking the more one-size-fits-all approach). In this case maybe substituting veg for fruit would still meet her challenge.
What 5 portions of veg would you typically eat in a day? 5 cups of peas? or spinach, carrots, tomato (fruit really), squash and aubergine? Describe your 5-a-day to this point. and how often you would actually achieve it. Do you try to ensure they are all different colours?
here, the current advice is for nine smaller portions, four of which should be fruit and 5 veg, because more smaller portions are easier to 'swallow"
and the greater number should lead to more variety.
I'm terrible, beest's great -he has about 5 pieces of fruit at work during the day, salad in his lunch and then veg with dinner. Although so far today I've had a large plum and 1/3 of a coconut and it's not yet 10am, this is far from typical for me.