Am I too old and do I have too long of break in service to rejoin?

There is somewhat a recent change to mandatory retirement for commissioned officers at age 62.

You will receive credit for your prior active duty time for retirement and age waiver for commissioning.

The needs of the service as you know comes first, and your bachelors degree can benefit your interest in joining again. I would encourage you to consider several branches of service, seek their officer recruiters and see what they have to offer.

I wish you all the best!

http://www.usphs.gov

Look at their comp sci (CS), IT, and engrg spots, as well as their Jr and Sr COSTEP, their analogues to ROTCs, I "think" they can be used for grad school...call their toll-free phone for their recrutiing ofc, and explain your background...you've got nothing to lose, plus, as I'd said, their age limits tend to be a good deal higher than other svcs...there are other direct commission aspects you could also look at in other svcs, esp law, if you might be at all inclined that way, as I'd explained, I'd need to know more to be able to give you more concrete ideas and/or possibilities, the more you send, the more I and/or others here can have to look through, however, try to be as specific as possible...also, what civilian work types you've done, even if only generally, whether they were supervisory at all...then, too, would you consider Guard? Reserve? Guard Tech? Reserve Tech? AGR? Possibly any of the state defense forces (SDFs), even though I realize you'd want Federal, I merely suggest it as an idea, that's all, honest, I'm entirely aware it likely wouldn't be your first preference, I'd expect, obv...Look through all those, and try to give us all more, as I'd said, esp specific actual coursework you've done, masters and PhD, stuff you might've tried at all and/or been inclined to try, in addn, and, esp, which other svcs you'd looked at, aside from solely Army, so far as possible, OK?

https://www.goarmy.com/army-cyber/cyber-direct-commissioning-program.html

And this....

You're as old as you are - I'm 64 , exercise regularly (3 mile in 21 minutes, etc...) not skinny/overweight, go hiking/camping through forest/mountains about once a month, kayak/canoe during some of those trips, climb and rappel about once a quarter.
I've got a right arm that doesn't work/bend correctly so I've developed some workarounds + I've fabricated some unpowered (due to my desire to not be tied to an electrical outlet) assists.
If you are physically (or can get that way) fit, then you have the call to do it. You might need some retraining to knock the rust off but you can do it.

As to the whole enlisted thing, I know you'd said you didn't want to go that route again, I get that, I merely saw you'd also said you wouldn't shy away from it...that being said, I do quite honestly think you've got enough that at least some of the warrant and/or commissioned approaches I'd sent might at least be serious possibles for you, if nothing else...lemme know what you think, I'd be most interested to hear more, esp a course list of specific coursework you've taken, as I'd said, as well as your genl thoughts about the other sites I'd sent, hope it's all of at least some possible use and/or interest, of course....

I would suggest to leave your options open for both enlisted and officer. As far as age, they are going to minus your total years of active service from your age so you’ll be good.
When I returned to active duty I had a 12 year break in service as well. Although I had 2 degrees I chose enlisted and I have no regrets!! Best decision I ever made and I’ve been back on active duty since December 2007..... Good luck to you

https://news.usni.org/2018/06/13/navy-implements-warrant-officer-1-rank-for-cyber-specialists

There's this....

Elaborate, if you can...major? Grades? GPA? Assocs before the bach, with same info, it any? Any grad school stuff at all? Would you be willing to look at other svcs? Any STEM coursework at all? Non-STEM? Specific course titles, if you can send them also, would help a good deal to be able to suggest stuff...lemme send some various ideas, if you'd wanna chat more, no rush, whenever you'd want, I tend to have an interest in career/educ stuff...also, the prior active might reduce your effective age for various svcs, though you'd need to be flexible, I'd expect...would you also consider warrant at all? Any cyber interests? Navy has a cyber warrant program, Army has its direct commission cyber program...then, too, if you'd be willing to consider it, USPHS uses comp sci (CS) as well as IT, in addn to engrg, you'd need to call their toll-free, their age limits tend to be about where you are now, though, as I'd said, your 6 yrs prior active should quite possibly count toward reducing your overall effective age for submitting...lemme send the other stuff I'd mentioned, so you can at least look through it, OK?