Geoflutterfire with where statement

[zpawlo02]

So when I'm trying to put ref like this:
var q = _firestore.collection('users').where('age', isGreaterThanOrEqualTo: minAge).where('age', isLessThanOrEqualTo: maxAge);
to:

Geoflutterfire geo = Geoflutterfire();
return geo.collection(collectionRef: q)
        .within(center: center, radius: radius, field: 'position');

I'm getting this error:

_Unhandled Exception: PlatformException(invalid_query, FIRInvalidArgumentException, Invalid query. You have a where filter with an inequality (lessThan, lessThanOrEqual, greaterThan, or greaterThanOrEqual) on field 'age' and so you must also use 'age' as your first queryOrderedBy field, but your first queryOrderedBy is currently on field 'position.geohash' instead.)
#0      StandardMethodCodec.decodeEnvelope (package:flutter/src/services/message_codecs.dart:569:7)
#1      MethodChannel._invokeMethod (package:flutter/src/services/platform_channel.dart:156:18)
<asynchronous suspension>
#2      MethodChannel.invokeMethod (package:flutter/src/services/platform_channel.dart:329:12)
#3      MethodChannelQuery.snapshots.<anonymous closure> (package:cloud_firestore_platform_interface/src/method_channel/method_channel_query.dart:55:50)
#4      _runGuarded (dart:async/stream_controller.dart:823:24)
#5      _BroadcastStreamController._subscribe (dart:async/broadcast_stream_contr<…>_

[ghost]

isGreaterThanOrEqualTo and isLessThanOrEqualTo appears to not work at all.