Tanya, At 60 yrs & 5'1" I share your concerns. In addition, I have an "iffy" back, so I make certain that I am carrying my gear correctly (posture), or I will have issues later. As others have said, we (my husband & I) only warm water dive & so have lighter/less gear. Yet, we mostly shore dive; so I carry the wt pouches/mask/ dsmb down separately from the tanks/bc/fins. Where I align the straps onto my tank also matters to my back (wt distribution) when walking a distance to the water. I make sure it is right "for me". I also always ask the dive shop we will be using, in advance (when planning the trip), if they have 63cu Nitrox tanks available for rent. If so, I arrange to use them; they seem to greatly lighten/better balance the load rather than the 80s. Some shops have taken extra steps to obtain them for me, which is MUCH appreciated. (I use less air than my husband, so the small 63s still works really well for me. It would depend on your air usage). When my back is worse, my husband will "lug" my gear down for me, but I prefer doing it myself as much as possible; yet there are days he places the tank/bc in the water for me & I just put it on.
Also, I see you have a couple dozen dives logged. Do make a conscious effort to reduce the lead wt you carry to only what is necessary (as others have said). I am now carrying 8# for shore diving, with 9/10# boat, swell, current diving. For whatever reason, on my first cert boat/ocean dives, I was set up with 16#. It was too much, made for difficult neutral buoyancy, & was really difficult to walk - geared up. I'm not sure where you are with that, but worth a consideration.
When boat diving, I ask in advance to be seated toward the back of the boat, so I don't have to walk as far in loaded gear. And if I am having a bad-back day, I request assistance from the crew with my water exit (removing my gear first, in water & handing it up). The boat crews have always been great & we tip extra for their help.
Lastly, I work hard to keep myself as physically fit as possible, including diet (biking, walking, sit-ups, push ups, planks, yoga, etc). I figure, when I am wet & fully loaded with gear, the last thing I need is to lug around another 10#s of my own excess fat! lol. Some sort of routine excercise is beneficial. Welcome to diving - it's magical! (I started late as well, at age 50).
PS. If relative strangers are assisting you with your gear, offer to tip them (& have it available), or show your appreciation verbally. The dive community is generally very helpful & inclusive. If you are doing your best, taking steps to be independent, and appreciative, this should weigh heavily in your favor.