H4>F1 Approved,F1 starts after 3 months. Can I exit+enter US on H4 before F1 date?

[p22]

Hello All,

Needed your urgent help on my case:

1. I'm on H4, and applied for CoS for H4 -> F1. Got F1 approved and I-797A.
2. My F1 start date on I-797 is, say 15th Dec

Questions:

1. Can I travel outside US and re-enter US on H4 - before F1 start date on I-797A (before 15th Dec)?
I don't want to go through the F1 stamping

2. At port of entry, would the Visa officers question me or see my visa status changing to F1 on 15th Dec?
Do I have to get F1 stamped, if I'm entering US before my F1 start date (while I am technically still on H4)?

Thanks in advance!

Regards,
P!