When I was breeding toy poodles & the girls came in heat I wore panties (made for dogs) on them. Some had cute designs & ruffles. They tied on & had a pocket for a pad. However I had one male that would get past them, he was that determined. He got so bad we had to cage him to give the girls a break. Some males can get quite aggressive around a female in heat. A male can smell a female in heat 3-5 miles away.
They wore the panties in the house & I removed them for outside potty time. Luckily I have a fenced in yard. The boys were put out after the girls came in. Talk about juggling dogs, LOL.
Rule of thumb: A heat cycle is usually 2-4 weeks, but my dogs were generally always 3 weeks. 7 days coming, 7 days in, & 7 days going. It can be a trying 2-4 weeks, especially if you don't have a fenced yard & have to do walks.
Since you do walks & the dog park I'd suggest only out long enough to go potty until heat cycle is over. If you must do walks, potty then put pants on right away, or wear pants & try to find a store that will permit you to do walks. Otherwise daily inside training sessions, challenge toys, etc. Here in PA taking dogs in public parks, stores, etc. is banned & only permitted for service dogs & leashed at all times. Dogs parks are permitted, if you're lucky to have one close by.
They also suggest putting a "dog in heat" spray on your dogs shoulders & tail before walking them. I'm not too keen on this, as many smell like menthol & your dog will smell like that.
I also agree to let females come in heat before getting fixed. It gives them time to mature & reach full growth. PA now has a law, thanks to irresponsible owners, that requires getting your dog fixed at age 6 months. Most vets do not agree. So it's good you are waiting.