بسم الله الرحمن الرحيم
Zakah becomes wajib on plot, flat, motor, vehicle etc only when the person buys them with the intention of selling as in such a case it is trading material. And zakah is wajib on trading materials provided the condition of zakah is found. And if someone bought plot, flat etc for his personal use or accommodation or with the intention of gifting it to someone or with the intention of making a will of, then as per the Shari’ah it is not trading material and hence no zakah shall be wajib on them. In the question mentioned above the plot and flat which you have bought you didn’t buy them with the intention of selling rather you bought them with the intention to gift to your elder and younger daughters at their marriages hence no zakah shall be wajib on the plot and flat.
لا زكاة فى اللآلئ والجواهر وإن ساوت ألفاً اتفاقاً إلا أن تكون للتجارة ، والأصل أن ما عدا الحجرين والسوائم إنما يزكي بنية التجارة الخ (الدر المختار مع رد المحتار ، كتاب الزكاة ، 3: 194، ط مكتبة زكريا ديوبند)
Allah knows Best!
Darul Uloom Deoband