Hi Tracy,
Yes, your walks are perfectly safe. Whether you have afib or flutter isn't possible to discern from the rate alone. Although you may well also have flutter, I think you may have misunderstood Shannon because 180 doesn't suggest flutter. It's more likely afib, especially since you experience dizziness, shortness of breath, etc. Flutter is less likely to produce those symptoms than afib.
When is your ablation? Are you on any rate or rhythm control meds?