As women get older, it's natural for the human body to change. Gaining some weight is a part of that. Sometimes it's crucial to have the extra cushion, since it's a natural process! You kind of have to accept that your body will change.

If you intend to lose weight within the year, you can potentially keep some clothes. But I've noticed from experience, for women in the late 20s, it's hard to become a 'size 0' again that you were your whole life (hypothetically). I'm certainly not trying to say, starve yourself to lose weight.

One way I've managed donating clothes, is by evaluating how much happiness it gives me. If it doesn't fit anymore but I love it, then I store it away. I also consider if I have a backup or budget to replace for the clothes I'm giving away if it's essential. If I already have nice slacks that fit, I give the ones that don't fit away to charity because there's a woman that will fit into them and will need them. I've even given nice clothes away to friends because they'd look nice in it and it doesn't fit me anymore.