Need Help Id'ing Penny Red With "75" Cancellation

I know this has been asked before but I have a unique situation that I know SOMEONE out there can help with.
I inherited some stamps that were in storage, most for at least 40 years. Some (including the one I am inquiring about) were boxed up for at least 100 years. Three generations boxed up and then passed down their postage stamps. I am currently organizing them. Many of the stamps are from Europe and a few from Great Britain. No one had access to these and I know the stamp I am asking about is authentic. I'd be happy to let an expert look at it but am having a difficult time finding people I can trust.
So here goes! Does this look like it's worth me paying for an expert appraisal?
THANK YOU IN ADVANCE FOR ANY ADVICE!!

Ok. But we need a better photo in order to help you.

1d reds themselves, unless one of the scarce (225) or rare (77) plates, are common stamps. The plate number can be found in the design on each side of Vicky's head.

Shelley, I am confused.
If you know it is authentic, why need an expert appraisal?

Postmark is Birmingham 4-2-2-4 Barred numeral 75
Usage dates
13th March 1848 to 25th January 1851

I meant AUTHENTIC as in really the age it's supposed to be. I used the wrong word. Until you just told me, I didn't even know the year so thank you for that! This is a new hobby so plan on me sounding ignorant.

I will get better photos for ya'll.

And everyone says the plate number is in the design but I have yet to know how to find it. What is the trick?

The numbers are finely engraved in the scrollwork in front of, and behind, Her Majesty's visage.
If you have a Magnifier.......these locations
Looks like 11 or 11?

PS: Well done on a very good thread title, unusual for a beginner.
A big tick

Is this any better?

Looks like plate 117 ?

Looks like plate 117. It is worth a few pounds in fine condition.

Minimal value, I'm afraid. Around 15,000,000 stamps from this plate were printed so good copies should be easy to find. Your stamp has "issues" regarding postmarking, perforations, centering. At least it has kept it's value.... cost one penny back when printed...worth that today also.

Hi Rod,

I'd question your postmark date.

From what I've read, this upright oval type first came into use in 1864 (as a general pattern, not specifically in Birmingham).

Also, Plate 117 was first used to print stamps in 1868.

Hi Nigel.
always nice to get advice from you, I learn lots.
I'll check my resource.
The print date of Plate 117 makes it certain I have made a wobbly somewhere.
Thanks

Update..I did, I did
I mis-read from 2 adjoining listings

Shelley
I still have it Birmingham (Upright Oval numeral 75) (No Dates of usage given)
Known applied in black and blue. Birmingham

I think it looks like 117 as well. I appreciate the help! Tremendously. I can't wait to get all this organized and show off the rest of my stamps. There are thousands, literally. I'll definitely be doing this for a good long while. Glad I found this site!! THANK YOU!!!!