Is this walking behaviour normal?

Looking for some advice. I have a 16 week old cockapoo. She listens well in the house/garden. She can sit/down. She does wait before eating etc. I’ve been doing walking training where she’s in heel position in the house/garden where I treat her when she’s engaged with me, she can do it for a quite a while in the garden 2/3 minutes at a time. We’ve taken her out to cafes etc and she can settle under the table with a chew. She’s met people/children/dogs but we don’t let her greet random people walking past

When she’s out on a walk she goes absolutely loopy. She’s nose to the ground 90% of the time. She does about 10 minutes then starts pinging in different directions. On the rare occasion she does greet a person/dog she gets the zoomies and I have to pick her up and take her away. Am I doing something wrong? Is it normal for this age?

Thanks for your help!