Have I been too clever for my own good? Oxygenated wort?

Hi all, my name is Ratso and up until two weeks ago it had been 12 years since my last brew. Once an addict, always an addict I suppose.

I decided to do a few small batches (7 litres, about 2G I think) using DME to get back into the swing of things. One thing I have learnt from this great site as I geared up to start brewing again is the idea of late extract additions. I have brewed two batches so far using 1kg (just over 2lb) of DME that comes in 500g packets. Logically enough I decided on starting the boil with one packet of the DME with the other packet getting chucked in at flame-out. I know how much of a pain DME is to stir into hot wort so I decided to mix the late addition DME with cold water first thereby creating a dilute LME which was easy to mix and easy to pour into the wort. However, I used a whisk to mix the DME to the cold water and thinking about it now I might have made a mistake by introducing oxygen to the late addition which is then obviously added to the boiling wort at flame-out.

Have I cocked up my first batch by oxygenating the wort? I understand that HSA isn't such a concern for us HBers these days but by whisking the DME pretty solidly I did create a lot of foam which was then poured into the wort. Fermentation seemed to go fine but will I find 7 litres of malt vinegar when I bottle next week (will then have been three weeks in primary) and should I maybe consider bottling now to try and get a few beers drunk before turning to vinegar.

Yeah, I know the relax mantra but it doesn't feel like I've started brewing again until posting a 'is my batch ruined' thread

You'll be fine. There needs to be some oxygenation so the yeasties can get started doing their thing. There's actually O2 kits and paddles to attach to cordless drills to oxygenate the wort right before pitching the yeast. I haven't used either if these put I do pour my wort for pot to fermenter pretty vigorously to introduce O2.

He's asking about hot side aeration.
I wouldn't worry much about it, Ratso. HSA is a sort of homebrew boogeyman. Mom used to tell you about the boogeyman to scare you into bed, and passively teach you about stranger danger, but there was never anyone in the closet. HSA is notable, and worthy of acknowledgement, but I wouldn't be concerned.