My concern with some of the advice that people are giving you here is that it is coming from their POV and is based on their experience.
Safety - do you lift correctly (appropriate form and breathing)? We can’t tell from your words.
Structure - can your body handle what you throw at it? Are your bones strong? Are you tendons strong enough to support the movements? Are you ligaments strong enough to hold your joints together? At 15, this would be my concern having never seen you lift and given that you say you’ve been at if for a few months.
Recruitment potential - can you fire the primary muscles? Many people can pull heavy but still fail to recruit their qlutes effectively. This may shift the load onto muscles that really shouldn’t be working during the movement or during a particular range of motion.
Structurally balance - can you engage the structural support muscles throughout the entire set? E.g. if your rotator cuff muscles are not up to task, there’s a good chance that the load vector will move into a biomechanically poor position increasing the likelihood of injury.
I’m going to say that the trainer at your local gym may be in a better position to answer your question than us because they actually see what you are doing - they may have picked up on the errors you are making and be giving you the best advice. We can’t see you so our “yes” or “no” really isn’t worth all that much.
Lifting is a life long thing so take the time when you are new at it to make sure you are able to do things correctly. Worst case you are ready now and spend a few month improving things that don’t really need it; best case you save yourself a serious injury and start at it hard when you’re 16. [/quote]
True, but those topics are true to any lifter. Physiologically there isn’t a reason that he shouldn’t be able to lift heavy right now givin good technique. I am not disagreeing with you, just elaborating; you are exactly right.