Is this sentence correct?
If not...
I guess 'did' instead of 'do' will be the better choice, but I just wonder if that sentence above can be used in the following situation. 

It's 8 a.m right now. I haven't started doing exercise yet and am about to do exercise in 10 min. I had breakfast 30 minutes ago. 

In that case, I don't think I can use the past tense 'did' cause I am not done any exercise yet .  

Can you help me with the sentence? Thank you so much in advance..