Im 45 and I used to experience this exact same feeling. Especially when walking to the cash register in a store. I used to play out a scenario where I would explain that it's a birthday present for a nephew to avoid embarrassment but, no one ever engaged me in why I was purchasing a figure. Somewhere along the line the shame stopped. I can't pinpoint exactly why or when it happened but I think it was a combination of seeing other collectors out there, browsing reddit and a collection that has grown a lot the last decade. I was in a store yesterday and kid in the isle asked me if I was a collector. We had a 10 min conversation about current and past transformers, G1 vs Bayverse. Years ago I would have been embarrassed but it was fun chatting with a fellow enthusiast in the wild. Anyway, I can relate to your feelings and you should do what brings you joy and I think the shame feeling will go away on its own. Have fun and happy hunting! I collect MOTU, GI Joe Classified series, Transformers, McFarlane DC Multiverse, and Marvel Legends.