Need help

So im super worried since its my first time having a hermanns tortoise and i have 9 months with him,(he is 9-10 months - ish old) i have everything he need like uvb heat food water etc. So today i squeezed his shell on the sides and was kinda flexible and just a bit soft (not on the top of the shell), but it comes back to shape. Same thing for his plastron. He is active, eats well and drinks water. I saw a similiar post made recently and OP had the same situation, comments said its okay but i think my tortoise is too old to still be slightly flexibly but i might be wrong. I dont know if it was like this before because i never check (please dont judge). If u have any idea if its something serious or harmless please tell me!