Is it hard to get hired by top tiers or higher pay for a 30 year old engineering master graduate from a Japan national university as a non native?

I am a Southeast Asia woman (27 years old now) and I will join graduate school in Japan (I have got Mext scholarship for master). specialization is electrical engineering.
I already have total 3 years of drafting experience in my country and in Thailand but it is not the same field with my major.

When I graduate, I will be 30.
Japanese is not that difficult for me as I have N2 certificate now and I still have 2 more years to graduate.
My question is that how hard it is for me based on my facts to get hired in a top tier company in Japan or with high salary.
I am worried about my age as 30 is too old compared to other graduates and for Japanese they graduate master around ~26~ years old.
My university is top 20 ranked national university. But I also have to compete with the Japanese at the same university for the high salary job. so, I would like to get some advice to prepare. And also the conditions now as a salary man if you are a salary man in Japan right now.

by daungbubu