Just keep in mind that their motivation for this may not be as pure as you think and you may find yourself wifeless once she has got citizenship/money through marrying you.
If you register at a Russian dating service (also known as internet dating /marriage agency) and find out that lots of much younger women are contacting you eagerly for dating - you will know for sure you have landed at a scam dating website.
Before eagerly grabbing a ‘bride' for yourself please pay attention to these indicators of the cultural differences between dating Bulgarian women and dating Russian women.
Bulgarian ladies have free access to Europe without a visa and can on the one hand easily find employment outside Bulgaria and on the other hand visit you without fiancée visa complications if you intend to take your relationship to the next level.
The reason for the slight difference in dating is the imbalance in the population in Russia; due to sheer lack of men it is simply harder to find a husband for Russian brides or Russian women.