At the very least the trailer needs to be roadworthy. Most trailers can be tweaked if necessary to make handling the glider easier - one essential for an Astir is a wing root dolly. It's not called the concrete swan without just cause.
Yes, the aluminium frame for the wheel can crack.
And as said by Kev - you should be asking your CFI what he thinks a suitable glider is. You could also ask whoever sent you solo, the chap or chaps that signed off your bronze flying tests.
Most important of all - do you fit it?